Fractions

ICSE Class 7 Mathematics · Solutions for Class 7 RS Aggarwal ICSE Foundation Mathematics · 83 solved questions

Exercise
Marks
1Exercise 2(A)

Find the product :

$\frac{5}{6} \times \frac{3}{7}$

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We have:

$$\begin{array}{ll} \phantom{=} \frac{5}{6} \times \frac{3}{7} \\\\ = \frac{5 \times 3}{6 \times 7} \\\\ = \frac{5 \times 1}{2 \times 7} & \text{[Simplifying 3 and 6 ⇒ Divide by 3 ]} \\\\ = \frac{5}{14} \\\\ \end{array}$$

∴ The answer is $\frac{5}{14}$

2Exercise 2(A)

Find the product :

$\frac{7}{18} \times \frac{9}{14}$

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We have:

$$\begin{array}{ll} \phantom{=} \frac{7}{18} \times \frac{9}{14} \\\\ = \frac{7 \times 9}{18 \times 14} \\\\ = \frac{7 \times 1}{2 \times 14} & \text{[Simplifying 9 and 18 ⇒ Divide by 9]} \\\\ = \frac{1 \times 1}{2 \times 2} & \text{[Simplifying 7 and 14 ⇒ Divide by 7]} \\\\ = \frac{1}{4} & \end{array}$$

∴ The answer is $\frac{1}{4}$

3Exercise 2(A)

Find the product :

$28 \times \frac{7}{8}$

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We have:

$$\begin{array}{ll} \phantom{=} 28 \times \frac{7}{8} \\\\ = \frac{28}{1} \times \frac{7}{8} \\\\ = \frac{7}{1} \times \frac{7}{2} & \text{[Simplifying 28 and 8 ⇒ Divide by 4]} \\\\ = \frac{7 \times 7}{1 \times 2} \\\\ = \frac{49}{2} & \\\\ = 24 \frac{1}{2} & \text{[Converting improper to mixed fraction]} \end{array}$$

∴ The answer is 24 $\frac{1}{2}$

4Exercise 2(A)

Find the product :

$7 \times \frac{1}{7}$

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We have:

$$\begin{array}{ll} \phantom{=} 7 \times \frac{1}{7} \\\\ = \frac{7}{1} \times \frac{1}{7} \\\\ = \frac{7 \times 1}{1 \times 7} \\\\ = \frac{7}{7} \\\\ = 1 & \text{[Dividing both by 7]} \end{array}$$

∴ The answer is 1

5Exercise 2(A)

Find the product :

$2\frac{1}{25} \times \frac{5}{17}$

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We have:

$$\begin{array}{ll} \phantom{=} 2\frac{1}{25} \times \frac{5}{17} \\\\ = \frac{51}{25} \times \frac{5}{17} & \text{[Converting mixed fraction to improper fraction]} \\\\ = \frac{51}{5} \times \frac{1}{17} & \text{[Simplifying 5 and 25 ⇒ Divide by 5]} \\\\ = \frac{3}{5} \times \frac{1}{1} & \text{[Simplifying 51 and 17 ⇒ Divide by 17]} \\\\ = \frac{3 \times 1}{5 \times 1} & \\\\ = \frac{3}{5} \end{array}$$

∴ The answer is $\frac{3}{5}$

6Exercise 2(A)

Find the product :

$1\frac{1}{13} \times 7\frac{3}{7}$

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We have:

$$\begin{array}{ll} \phantom{=} 1\frac{1}{13} \times 7\frac{3}{7} \\\\ = \frac{14}{13} \times \frac{52}{7} & \text{[Converting mixed fraction to improper fraction]} \\\\ = \frac{2}{13} \times \frac{52}{1} & \text{[Simplifying 14 and 7 ⇒ Divide by 7]} \\\\ = \frac{2}{1} \times \frac{4}{1} & \text{[Simplifying 52 and 13 ⇒ Divide by 13]} \\\\ = \frac{2 \times 4}{1 \times 1} \\\\ = \frac{8}{1} \\\\ = 8 \end{array}$$

∴ The answer is 8

7Exercise 2(A)

Find the product :

$\frac{4}{17} \times 7\frac{1}{12}$

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We have:

$$\begin{array}{ll} \phantom{=} \frac{4}{17} \times 7\frac{1}{12} \\\\ = \frac{4}{17} \times \frac{85}{12} & \text{[Converting mixed fraction to improper fraction]} \\\\ = \frac{4}{1} \times \frac{5}{12} & \text{[Simplifying 85 and 17 ⇒ Divide by 17 ]} \\\\ = \frac{1}{1} \times \frac{5}{3} & \text{[Simplifying 4 and 12 ⇒ Divide by 4 ]} \\\\ = \frac{1 \times 5}{1 \times 3} \\\\ = \frac{5}{3} \end{array}$$

∴ The answer is $\frac{5}{3}$

8Exercise 2(A)

Find the product :

$7\frac{1}{4}\times\frac{7}{58}\times1\frac{11}{21}$

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We have:

$$\begin{array}{ll} \phantom{=} 7\frac{1}{4}\times\frac{7}{58}\times1\frac{11}{21} \\\\ = \frac{29}{4} \times \frac{7}{58} \times \frac{32}{21} & \text{[Converting mixed fraction to improper fraction]} \\\\ = \frac{1}{4} \times \frac{7}{2} \times \frac{32}{21} & \text{[Simplifying 29 and 58 ⇒ Divide by 29 ]} \\\\ = \frac{1}{4} \times \frac{1}{2} \times \frac{32}{3} & \text{[Simplifying 7 and 21 ⇒ Divide by 7 ]} \\\\ = \frac{1}{1} \times \frac{1}{2} \times \frac{8}{3} & \text{[Simplifying 32 and 4 ⇒ Divide by 4 ]} \\\\ = \frac{1 \times 1 \times 8}{1 \times 2 \times 3} \\\\ = \frac{8}{6} \\\\ = \frac{4}{3} & \text{[Dividing both by 2]} \\\\ = 1\frac{1}{3} & \text{[Converting improper to mixed fraction]} \end{array}$$

∴ The answer is $1\frac{1}{3}$

9Exercise 2(A)

Find the product :

$\frac{1}{19}\times91\times5\frac{11}{13}$

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We have:

$$\begin{array}{ll} \phantom{=} \frac{1}{19}\times91\times5\frac{11}{13} \\\\ = \frac{1}{19} \times \frac{91}{1} \times \frac{76}{13} & \text{[Converting mixed fraction to improper fraction]} \\\\ = \frac{1}{19} \times \frac{7}{1} \times \frac{76}{1} & \text{[Simplifying 91 and 13 ⇒ Divide by 13 ]} \\\\ = \frac{1}{1} \times \frac{7}{1} \times \frac{4}{1} & \text{[Simplifying 76 and 19 ⇒ Divide by 19 ]} \\\\ = \frac{1 \times 7 \times 4}{1 \times 1 \times 1} \\\\ = \frac{28}{1} \\\\ = 28 \end{array}$$

∴ The answer is 28

10Exercise 2(A)

Find the product :

$7\frac{1}{4}\times2\frac{3}{16}\times2\frac{2}{7}$

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We have:

$$\begin{array}{ll} \phantom{=} 7\frac{1}{4}\times2\frac{3}{16}\times2\frac{2}{7} \\\\ = \frac{29}{4} \times \frac{35}{16} \times \frac{16}{7} & \text{[Converting mixed fraction to improper fraction]} \\\\ = \frac{29}{4} \times \frac{35}{1} \times \frac{1}{7} & \text{[Simplifying 16 and 16 ⇒ Divide by 16 ]} \\\\ = \frac{29}{4} \times \frac{5}{1} \times \frac{1}{1} & \text{[Simplifying 35 and 7 ⇒ Divide by 7 ]} \\\\ = \frac{29 \times 5 \times 1}{4 \times 1 \times 1} \\\\ = \frac{145}{4} \\\\ = 36\frac{1}{4} & \text{[Converting improper to mixed fraction]} \end{array}$$

∴ The answer is $36\frac{1}{4}$

11(i)Exercise 2(A)

Find the value of :

$\frac{3}{4}$ of $\frac{8}{9}$

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We have:

$\frac{3}{4}$ of $\frac{8}{9}$

$$\begin{array}{ll} = \frac{8}{9} \times \frac{3}{4} \\\\ = \frac{2}{9} \times \frac{3}{1} & \text{[Simplifying 8 and 4 ⇒ Divide by 4 ]} \\\\ = \frac{2}{3} \times \frac{1}{1} & \text{[Simplifying 3 and 9 ⇒ Divide by 3 ]} \\\\ = \frac{2 \times 1}{3 \times 1} \\\\ = \frac{2}{3} \end{array}$$

∴ The answer is $\frac{2}{3}$

11(ii)Exercise 2(A)

Find the value of :

$\frac{1}{2}$ of $2\frac{2}{3}$

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We have:

$\frac{1}{2}$ of $2\frac{2}{3}$

$$\begin{array}{ll} = \frac{8}{3} \times \frac{1}{2} & \text{[Converting mixed fraction to improper fraction]} \\\\ = \frac{4}{3} \times \frac{1}{1} & \text{[Simplifying 8 and 2 ⇒ Divide by 2 ]} \\\\ = \frac{4}{3} \\\\ = 1\frac{1}{3} & \text{[Converting improper to mixed fraction]} \end{array}$$

∴ The answer is 1 $\frac{1}{3}$

11(iii)Exercise 2(A)

Find the value of :

$\frac{4}{5}$ of 1 hour

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We have:

$\frac{4}{5}$ of 1 hour

$$\begin{array}{ll} 1 \text{ hour} = 60 \text{ minutes} & \text{[Converting hour into minutes]} \\\\ = \Big(60 \times \frac{4}{5}\Big) \text{ minutes} \\\\ = \Big(\frac{60}{1} \times \frac{4}{5}\Big) \text{ minutes} \\\\ = \Big(\frac{12}{1} \times \frac{4}{1}\Big) \text{ minutes} & \text{[Simplifying 60 and 5 ⇒ Divide by 5 ]} \\\\ = \frac{48}{1} \text{ minutes} \\\\ = 48 \text{ minutes} \end{array}$$

∴ The answer is 48 minutes

11(iv)Exercise 2(A)

Find the value of :

$\frac{3}{5}$ of ₹1

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We have:

$\frac{3}{5}$ of ₹1

₹1 = 100 paise $\hspace{1.5cm}$[Converting rupees into paise]

$$\begin{array}{ll} = \Big(100 \times \frac{3}{5}\Big) \text{ paise} \\\\ = \Big(\frac{100}{1} \times \frac{3}{5}\Big) \text{ paise} \\\\ = \Big(\frac{20}{1} \times \frac{3}{1}\Big)\text{ paise} & \text{[Simplifying 100 and 5 ⇒ Divide by 5 ]} \\\\ = \Big(\frac{20 \times 3}{1 \times 1}\Big)\text{ paise} \\\\ = \frac{60}{1}\text{ paise} \\\\ = 60\text{ paise} \end{array}$$

∴ The answer is 60 paise

11(v)Exercise 2(A)

Find the value of :

$\frac{8}{15}$ of $1\frac{1}{2}$ metres

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We have:

$\frac{8}{15}$ of $1\frac{1}{2}$ metres

$1\frac{1}{2}$ metres = $\frac{3}{2}$ metres $\hspace{1.5cm}$[Converting mixed to improper fraction]

1 meter = 100 cm

∴$\frac{3}{2}$ metres = 150 cm $\hspace{1.5cm}$[Converting meter to centimeter]

Now we have:

$\frac{8}{15}$ of 150 centimetres

$$\begin{array}{ll} = \Big(150 \times \frac{8}{15}\Big) \text{ cm} \\\\ = \Big(\frac{150}{1} \times \frac{8}{15}\Big) \text{ cm} \\\\ = \Big(\frac{10}{1} \times \frac{8}{1}\Big) \text{ cm} & \text{[Simplifying 150 and 15 ⇒ Divide by 15 ]} \\\\ = \Big(\frac{10 \times 8}{1 \times 1}\Big) \text{ cm} \\\\ = \frac{80}{1} \text{ cm} \\\\ = 80 \text{ cm} \end{array}$$

∴ The answer is 80 cm

11(vi)Exercise 2(A)

Find the value of :

$\frac{5}{7}$ of $2\frac{1}{3}$kg

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We have:

$\frac{5}{7}$ of $2\frac{1}{3}$kg

$2\frac{1}{3}\text{ kg} = \frac{7}{3}\text{ kg} \hspace{1.5cm}$[Converting mixed to improper fraction]

Now we have:

$\frac{5}{7}$ of $\frac{7}{3}$ kg

$$\begin{array}{ll} = \Big(\frac{7}{3} \times \frac{5}{7}\Big) \text{ kg} \\\\ = \Big(\frac{1}{3} \times \frac{5}{1}\Big) \text{ kg} & \text{[Simplifying 7 and 7 ⇒ Divide by 7 ]} \\\\ = \Big(\frac{1 \times 5}{3 \times 1}\Big) \text{ kg} \\\\ = \frac{5}{3} \text{ kg} \\\\ = 1\frac{2}{3} \text{ kg} & \text{[Converting improper to mixed fraction]} \end{array}$$

∴ The answer is $1\frac{2}{3}$ kg

12Exercise 2(A)

A car can travel $12\frac{1}{2}$km in 1 litre of petrol. How much distance can it travel in $42\frac{3}{5}$ litres of petrol?

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Given:

Distance travelled in 1 litre of petrol = $12\frac{1}{2}$ km

= $\frac{25}{2}$ km $\hspace{1cm}$ [Converting mixed to improper fraction]

Distance travelled in $42\frac{3}{5}$ litres of petrol = ?

Number of litres = $42\frac{3}{5}$ = $\frac{213}{5}$ litres

Distance travelled in $\frac{213}{5}$ litres of petrol = (Distance travelled in 1 litre) x (Number of litres)

Substituting the values in above, we get:

$$\begin{array}{ll} = \Big(\frac{25}{2} \times \frac{213}{5}\Big)\text{ km} \\\\ = \Big(\frac{5}{2} \times \frac{213}{1}\Big)\text{ km} & \text{[Simplifying 25 and 5 ⇒ Divide by 5 ]} \\\\ = \Big(\frac{5 \times 213}{2 \times 1}\Big) \text{ km} \\\\ = \frac{1065}{2}\text{ km} \\\\ = 532 \frac{1}{2}\text{ km} & \text{[Converting improper fraction to mixed fraction]} \end{array}$$

∴ The distance travelled in $42\frac{3}{5}$ litres of petrol = $532\frac{1}{2}$ km.

13Exercise 2(A)

A graphic designer charges ₹$27\frac{3}{5}$ for each diagram. Find the amount he will charge if he designs 186 diagrams for a book.

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Given:

Charge of 1 diagram = ₹$27\frac{3}{5} = ₹\frac{138}{5}$

Charge for 186 diagrams = ?

Number of diagrams = 186

Charge for 186 diagrams = (Charge of 1 diagram) x (Number of diagrams)

Substituting the values in above, we get:

$$\begin{array}{ll} = ₹\Big(\frac{138}{5} \times 186\Big) \\\\ = ₹\Big(\frac{138 \times 186}{5 \times 1}\Big) \\\\ = ₹\frac{25668}{5} \\\\ = ₹5133\frac{3}{5} & \text{[Converting improper fraction to mixed fraction]} \end{array}$$

∴ The charge for 186 diagrams = ₹ $5133\frac{3}{5}$.

14Exercise 2(A)

If a cloth costs ₹$715\frac{1}{4}$ per metre, find the cost of $3\frac{2}{5}$ metres of this cloth.

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Cost of 1 meter of cloth = ₹$715\frac{1}{4} = ₹\frac{2861}{4}$

Cost of $3\frac{2}{5}$ meters of cloth = ?

Length of cloth = $3\frac{2}{5} \text{ meters} = \frac{17}{5}$ meters

Cost of $3\frac{2}{5}$ meters of cloth = (Cost of 1 meter of cloth) x (Length of cloth)

Substituting the values in above, we get:

$$\begin{array}{ll} = ₹\Big(\frac{2861}{4} \times \frac{17}{5}\Big) \\\\ = ₹\Big(\frac{2861 \times 17}{4 \times 5}\Big) \\\\ = ₹\frac{48637}{20} \\\\ = ₹2431\frac{17}{20} & \text{[Converting improper to mixed fraction]} \end{array}$$

∴ The cost of $3\frac{2}{5}$ meters of cloth = ₹ $2431\frac{17}{20}$.

15Exercise 2(A)

Advertising in a magazine costs ₹$1472\frac{2}{5}$ per square inch. Find the cost of an advertisement of $17\frac{6}{7}$ square inch.

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Cost of an advertisement of 1 square inch = ₹$1472\frac{2}{5} = ₹\frac{7362}{5}$

Cost of an advertisement of $17\frac{6}{7}$ square inch = ?

Area of an advertisement = $17\frac{6}{7}$ square inch

Cost of an advertisement of $17\frac{6}{7}$ square inch = (Cost of an advertisement of 1 square inch) x (Area of an advertisement)

Substituting the values in above, we get:

$$\begin{array}{ll} = ₹\Big(\frac{7362}{5} \times 17\frac{6}{7}\Big) \\\\ = ₹\Big(\frac{7362}{5} \times \frac{125}{7}\Big) & \text{[Converting mixed to improper fraction]} \\\\ = ₹\Big(\frac{7362}{1} \times \frac{25}{7}\Big) \\\\ = ₹\Big(\frac{7362 \times 25}{1 \times 7}\Big) \\\\ = ₹\frac{184050}{7} \\\\ = ₹26292 \frac{6}{7} & \text{[Converting improper fraction to mixed fraction]} \end{array}$$

∴ The cost of an advertisement of $17\frac{6}{7}$ square inch = ₹ $26292\frac{6}{7}$.

16Exercise 2(A)

A car travelled from city A to city B with a uniform speed of $52\frac{2}{7}$ km per hour. Find the distance between the two cities, if it took $4\frac{3}{8}$ hours for the car to reach city B from city A.

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Given:

Speed = $52\frac{2}{7}$ km/hour

Time = $4\frac{3}{8}$ hours

Distance = ?

We know the formula,

Distance = Speed x Time

By substituting the values we get,

$$\begin{array}{ll} \text{Distance} = \Big(52\frac{2}{7} \times 4\frac{3}{8}\Big) \text{ km} & \space \\\\ = \Big(\frac{366}{7} \times \frac{35}{8}\Big) \text{ km} & \text{[Converting mixed to improper fraction]} \\\\ = \Big(\frac{366}{1} \times \frac{5}{8}\Big)\text{ km} & \text{[Simplifying 35 and 7 ⇒ Divide by 7 ]} \\\\ = \frac{366 \times 5}{1 \times 8}\text{ km} \\\\ = \frac{1830}{8} \text{ km} \\\\ = 228\frac{3}{4}\text{ km} & \text{[Converting improper to mixed fraction]} \end{array}$$

∴ The distance between two cities is $228\frac{3}{4}$ km.

17Exercise 2(A)

The length of a rectangular plot of land is $29\frac{3}{7}$m. If its breadth is $12\frac{8}{11}$m, find its area.

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Given:

Length of a rectangular plot of land = $29\frac{3}{7}$ m

Breadth of a rectangular plot of land = $12\frac{8}{11}$ m

Area of a rectangular plot of land = ?

We know the formula,

Area of rectangle = Length x Breadth

By substituting the values we get,

Area of rectangle = Length x Breadth

$$\begin{array}{ll} = \Big(29\frac{3}{7} \times 12\frac{8}{11}\Big) \text{m}^2 \\\\ = \Big(\frac{206}{7} \times \frac{140}{11}\Big) \text{m}^2 & \text{ [Converting mixed to improper fraction]} \\\\ = \Big(\frac{206}{1} \times \frac{20}{11}\Big)\text{m}^2 & \text{[Simplifying 140 and 7 ⇒ Divide by 7 ]} \\\\ = \frac{206 \times 20}{1 \times 11} \text{m}^2 \\\\ = \frac{4120}{11}\text{m}^2 \\\\ = 374\frac{6}{11}\text{m}^2 & \text{[Converting improper to mixed fraction]} \end{array}$$

∴ The area of a rectangular plot of land is $374\frac{6}{11}$ m2

1(i)Exercise 2(B)

Find the reciprocal of :

$\frac{13}{17}$

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We have:

$\frac{13}{17}$

To find the reciprocal of a number, we interchange its numerator and denominator.

$\frac{13}{17}$ = $\frac{17}{13}$

= $1\frac{4}{13} \hspace{2cm}\text{[Converting improper to mixed fraction]}$

∴ The reciprocal of $\frac{13}{17}$ is $1\frac{4}{13}$

1(ii)Exercise 2(B)

Find the reciprocal of :

$\frac{3}{313}$

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We have:

$\frac{3}{313}$

Interchanging its numerator and denominator we get,

$\frac{3}{313}$ = $\frac{313}{3}$

= $104\frac{1}{3} \hspace{2cm}\text{[Converting improper to mixed fraction]}$

∴ The reciprocal of $\frac{3}{313}$ is $104\frac{1}{3}$

1(iii)Exercise 2(B)

Find the reciprocal of :

217

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We have:

217

This can be written as $\frac{217}{1}$

Interchanging its numerator and denominator we get,

$\frac{217}{1}$ = $\frac{1}{217}$

∴ The reciprocal of $\frac{217}{1}$ is $\frac{1}{217}$

1(iv)Exercise 2(B)

Find the reciprocal of :

$\frac{1}{1024}$

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We have:

$\frac{1}{1024}$

Interchanging its numerator and denominator we get,

$\frac{1}{1024}$ = $\frac{1024}{1}$ = 1024

∴ The reciprocal of $\frac{1}{1024}$ is 1024

1(v)Exercise 2(B)

Find the reciprocal of :

$3\frac{1}{3}$

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We have:

$3\frac{1}{3} = \frac{10}{3} \hspace{1.5cm}\text{[Converting mixed to improper fraction]}$

Interchanging its numerator and denominator we get,

$\frac{10}{3}$ = $\frac{3}{10}$

∴ The reciprocal of $\frac{10}{3}$ is $\frac{3}{10}$

1(vi)Exercise 2(B)

Find the reciprocal of :

$11\frac{1}{11}$

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We have:

$11\frac{1}{11}$ = $\frac{122}{11} \hspace{1.5cm}\text{[Converting mixed to improper fraction]}$

Interchanging its numerator and denominator we get,

$\frac{122}{11} = \frac{11}{122}$

∴ The reciprocal of $\frac{122}{11}$ is $\frac{11}{122}$

1(vii)Exercise 2(B)

Find the reciprocal of :

$1\frac{1}{2}$

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We have:

$1\frac{1}{2} = \frac{3}{2} \hspace{1.5cm}\text{[Converting mixed to improper fraction]}$

Interchanging its numerator and denominator we get,

$\frac{3}{2}$ = $\frac{2}{3}$

∴ The reciprocal of $\frac{3}{2}$ is $\frac{2}{3}$

1(viii)Exercise 2(B)

Find the reciprocal of :

$125\frac{1}{8}$

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We have:

$125\frac{1}{8} = \frac{1001}{8} \hspace{1.5cm}\text{[Converting mixed to improper fraction]}$

Interchanging its numerator and denominator we get,

$\frac{1001}{8}$ = $\frac{8}{1001}$

∴ The reciprocal of $\frac{1001}{8}$ is $\frac{8}{1001}$

2(i)Exercise 2(B)

Divide :

$\frac{1}{2}$ ÷ $\frac{1}{3}$

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We have:

$$\begin{array}{ll} \phantom{=} \frac{1}{2} ÷ \frac{1}{3} \\\\ = \frac{1}{2} \times \frac{3}{1} & [\text{Reciprocal of } \frac{1}{3} \text{ is } \frac{3}{1}] \\\\ = \frac{1 \times 3}{2 \times 1} \\\\ = \frac{3}{2} \\\\ = 1\frac{1}{2} \end{array}$$

∴ The answer is $1\frac{1}{2}$

2(ii)Exercise 2(B)

Divide :

$\frac{3}{14}$ ÷ $\frac{11}{42}$

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We have:

$$\begin{array}{ll} \phantom{=} \frac{3}{14} ÷ \frac{11}{42} \\\\ = \frac{3}{14} \times \frac{42}{11} & [\text{Reciprocal of } \frac{11}{42} \text{ is } \frac{42}{11}] \\\\ = \frac{3 \times 42}{14 \times 11} \\\\ = \frac{3 \times 3}{1 \times 11} & \text{[Simplifying 42 and 14 ⇒ Divide by 14]} \\\\ = \frac{9}{11} \\\\ \end{array}$$

∴ The answer is $\frac{9}{11}$

2(iii)Exercise 2(B)

Divide :

1 ÷ $6\frac{2}{3}$

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We have:

$$\begin{array}{ll} \phantom{=} 1 ÷ 6\frac{2}{3} \\\\ = 1 ÷ \frac{20}{3} & \text{[Converting mixed to improper fraction]} \\\\ = 1 \times \frac{3}{20} & [\text{Reciprocal of } \frac{20}{3} \text{ is } \frac{3}{20}] \\\\ = \frac{1}{1} \times \frac{3}{20} \\\\ = \frac{1 \times 3}{1 \times 20} \\\\ = \frac{3}{20} \\\\ \end{array}$$

∴ The answer is $\frac{3}{20}$

2(iv)Exercise 2(B)

Divide :

$13\frac{1}{3}$ ÷ 10

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We have:

$$\begin{array}{ll} \phantom{=} 13\frac{1}{3} ÷ 10 \\\\ = \frac{40}{3} ÷ 10 & \text{[Converting mixed to improper fraction]} \\\\ = \frac{40}{3} \times \frac{1}{10} & [\text{Reciprocal of } 10 \text{ is } \frac{1}{10}] \\\\ = \frac{4}{3} \times \frac{1}{1} & \text{[Simplifying 40 and 10 ⇒ Divide by 10]} \\\\ = \frac{4 \times 1}{3 \times 1} \\\\ = \frac{4}{3} \\\\ = 1\frac{1}{3} \end{array}$$

∴ The answer is $1\frac{1}{3}$

2(v)Exercise 2(B)

Divide :

$12\frac{1}{12}$ ÷ $\frac{5}{36}$

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We have:

$$\begin{array}{ll} \phantom{=} 12\frac{1}{12} ÷ \frac{5}{36} \\\\ = \frac{145}{12} ÷ \frac{5}{36} & \text{[Converting mixed to improper fraction]} \\\\ = \frac{145}{12} \times \frac{36}{5} & [\text{Reciprocal of } \frac{5}{36} \text{ is } \frac{36}{5}] \\\\ = \frac{29}{12} \times \frac{36}{1} & \text{[Simplifying 145 and 5 ⇒ Divide by 5]} \\\\ = \frac{29}{1} \times \frac{3}{1} & \text{[Simplifying 36 and 12 ⇒ Divide by 12]} \\\\ = \frac{29 \times 3}{1 \times 1} \\\\ = \frac{87}{1} \\\\ = 87 \end{array}$$

∴ The answer is 87

2(vi)Exercise 2(B)

Divide :

$\frac{13}{46}$ ÷ $2\frac{1}{11}$

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We have:

$$\begin{array}{ll} \phantom{=} \frac{13}{46} ÷ 2\frac{1}{11} \\\\ = \frac{13}{46} ÷ \frac{23}{11} & \text{[Converting mixed to improper fraction]} \\\\ = \frac{13}{46} \times \frac{11}{23} & [\text{Reciprocal of } \frac{23}{11} \text{ is } \frac{11}{23}] \\\\ = \frac{13 \times 11}{46 \times 23} \\\\ = \frac{143}{1058} \end{array}$$

∴ The answer is $\frac{143}{1058}$

2(vii)Exercise 2(B)

Divide :

$\frac{20}{31}$ ÷ 54

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We have:

$$\begin{array}{ll} \phantom{=} \frac{20}{31} ÷ 54 \\\\ = \frac{20}{31} \times \frac{1}{54} & [\text{Reciprocal of } 54 \text{ is } \frac{1}{54}] \\\\ = \frac{10}{31} \times \frac{1}{27} & \text{[Simplifying 20 and 54 ⇒ Divide by 2]} \\\\ = \frac{10 \times 1}{31 \times 27} \\\\ = \frac{10}{837} \end{array}$$

∴ The answer is $\frac{10}{837}$

2(viii)Exercise 2(B)

Divide :

$9\frac{4}{5}$ ÷ $3\frac{23}{25}$

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We have:

$$\begin{array}{ll} \phantom{=} 9\frac{4}{5} ÷ 3\frac{23}{25} \\\\ = \frac{49}{5} ÷ \frac{98}{25} & \text{[Converting mixed to improper fraction]} \\\\ = \frac{49}{5} \times \frac{25}{98} & [\text{Reciprocal of } \frac{98}{25} \text{ is } \frac{25}{98}] \\\\ = \frac{1}{5} \times \frac{25}{2} & \text{[Simplifying 49 and 98 ⇒ Divide by 49]} \\\\ = \frac{1}{1} \times \frac{5}{2} & \text{[Simplifying 25 and 5 ⇒ Divide by 5]} \\\\ = \frac{1 \times 5}{1 \times 2} \\\\ = \frac{5}{2} \\\\ = 2\frac{1}{2} \end{array}$$

∴ The answer is $2\frac{1}{2}$

2(ix)Exercise 2(B)

Divide :

$32\frac{1}{2}$ ÷ $8\frac{3}{4}$

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We have:

$$\begin{array}{ll} \phantom{=} 32\frac{1}{2} ÷ 8\frac{3}{4} \\\\ = \frac{65}{2} ÷ \frac{35}{4} & \text{[Converting mixed to improper fraction]} \\\\ = \frac{65}{2} \times \frac{4}{35} & [\text{Reciprocal of } \frac{35}{4} \text{ is } \frac{4}{35}] \\\\ = \frac{13}{2} \times \frac{4}{7} & \text{[Simplifying 65 and 35 ⇒ Divide by 5]} \\\\ =\frac{13}{1} \times \frac{2}{7} & \text{[Simplifying 4 and 2 ⇒ Divide by 2]} \\\\ = \frac{13 \times 2}{1 \times 7} \\\\ = \frac{26}{7} \\\\ = 3\frac{5}{7} \end{array}$$

∴ The answer is $3\frac{5}{7}$

2(x)Exercise 2(B)

Divide :

$8\frac{1}{21}$ ÷ $1\frac{6}{7}$

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We have:

$$\begin{array}{ll} \phantom{=} 8\frac{1}{21} ÷ 1\frac{6}{7} \\\\ = \frac{169}{21} ÷ \frac{13}{7} & \text{[Converting mixed to improper fraction]} \\\\ = \frac{169}{21} \times \frac{7}{13} & [\text{Reciprocal of } \frac{13}{7} \text{ is} \frac{7}{13}] \\\\ = \frac{13}{21} \times \frac{7}{1} & \text{[Simplifying 169 and 13 ⇒ Divide by 13]} \\\\ = \frac{13}{3} \times \frac{1}{1} & \text{[Simplifying 7 and 21 ⇒ Divide by 7]} \\\\ = \frac{13 \times 1}{3 \times 1} \\\\ = \frac{13}{3} \\\\ = 4\frac{1}{3} \end{array}$$

∴ The answer is $4\frac{1}{3}$

2(xi)Exercise 2(B)

Divide :

$6\frac{3}{16}$ ÷ $3\frac{1}{7}$

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We have:

$$\begin{array}{ll} \phantom{=} 6\frac{3}{16} ÷ 3\frac{1}{7} \\\\ = \frac{99}{16} ÷ \frac{22}{7} & \text{[Converting mixed to improper fraction]} \\\\ = \frac{99}{16} \times \frac{7}{22} & [\text{Reciprocal of } \frac{22}{7} \text{ is } \frac{7}{22}] \\\\ = \frac{9}{16} \times \frac{7}{2} & \text{[Simplifying 99 and 22 ⇒ Divide by 11]} \\\\ = \frac{9 \times 7}{16 \times 2} \\\\ = \frac{63}{32} \\\\ = 1\frac{31}{32} \end{array}$$

∴ The answer is $1\frac{31}{32}$

2(xii)Exercise 2(B)

Divide :

$3\frac{11}{15}$ ÷ $19\frac{3}{5}$

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We have:

$$\begin{array}{ll} \phantom{=} 3\frac{11}{15} ÷ 19\frac{3}{5} \\\\ = \frac{56}{15} ÷ \frac{98}{5} & \text{[Converting mixed to improper fraction]} \\\\ = \frac{56}{15} \times \frac{5}{98} & [\text{Reciprocal of } \frac{98}{5} \text{ is } \frac{5}{98}] \\\\ = \frac{56}{3} \times \frac{1}{98} & \text{[Simplifying 5 and 15 ⇒ Divide by 5]} \\\\ = \frac{4}{3} \times \frac{1}{7} & \text{[Simplifying 56 and 98 ⇒ Divide by 14]} \\\\ = \frac{4 \times 1}{3 \times 7} \\\\ = \frac{4}{21} \end{array}$$

∴ The answer is $\frac{4}{21}$

3Exercise 2(B)

By what fraction should $\frac{9}{35}$ be multiplied to get $\frac{7}{15}$ ?

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Given:

The fraction by which $\frac{9}{35}$ must be multiplied to get $\frac{7}{15}$ = ?

Let the required fraction be x

Now we have,

$\frac{9}{35} \times x = \frac{7}{15}$

x = $\frac{7}{15} ÷ \frac{9}{35}$

$$\begin{array}{ll} = \frac{7}{15} \times \frac{35}{9} & [\text{Reciprocal of } \frac{9}{35} \text{ is } \frac{35}{9}] \\\\ = \frac{7}{3} \times \frac{7}{9} & \text{[Simplifying 35 and 15 ⇒ Divide by 5]} \\\\ = \frac{7 \times 7}{3 \times 9} \\\\ = \frac{49}{27} \\\\ = 1\frac{22}{27} \end{array}$$

∴ The answer is $1\frac{22}{27}$

4Exercise 2(B)

If the cost of $6\frac{1}{4}$ m of cloth is ₹$1421\frac{7}{8}$, then find the cost of 1 metre of cloth.

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Given:

Total cost = ₹$1421\frac{7}{8} = ₹\frac{11375}{8}$

Total length = $6\frac{1}{4}\text{ m} = \frac{25}{4}\text{ m}$

Cost of 1 metre of cloth = ?

Cost of 1 metre of cloth = (Total cost) ÷ (Total length)

Substituting the values in above, we get:

Cost of 1 metre of cloth = ₹ $\frac{11375}{8} ÷ \frac{25}{4}$ m

$$\begin{array}{ll} = ₹\Big(\frac{11375}{8} \times \frac{4}{25}\Big) & [\text{Reciprocal of } \frac{25}{4} \text{ is } \frac{4}{25}] \\\\ = ₹\Big(\frac{455}{8} \times \frac{4}{1}\Big) & \text{[Simplifying 11375 and 25 ⇒ Divide by 25]} \\\\ = ₹\Big(\frac{455}{2} \times \frac{1}{1}\Big) & \text{[Simplifying 4 and 8 ⇒ Divide by 4]} \\\\ = ₹\frac{455 \times 1}{2 \times 1} \\\\ = ₹\frac{455}{2} \\\\ = ₹227\frac{1}{2} \end{array}$$

∴ The cost of 1 metre of cloth = ₹$227\frac{1}{2}$

5Exercise 2(B)

How many pieces of length $3\frac{5}{7}$m each can be cut from a wall paper 52 m long?

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Given:

Piece length = $3\frac{5}{7}$ m = $\frac{26}{7}$ m $\hspace{1.5cm}\text{[Converting mixed to improper fraction]}$

Total length = 52 m

Number of pieces = ?

Number of pieces = (Total length) ÷ (Piece length)

Substituting the values in above, we get:

Number of pieces = 52 m ÷ $\frac{26}{7}$ m

$$\begin{array}{ll} = \Big(\frac{52}{1} \times \frac{7}{26}\Big) & [\text{Reciprocal of } \frac{26}{7} \text{ is } \frac{7}{26}] \\\\ = \Big(\frac{2}{1} \times \frac{7}{1}\Big) & \text{[Simplifying 52 and 26 ⇒ Divide by 26]} \\\\ = \Big(\frac{2 \times 7}{1 \times 1}\Big) \\\\ = \frac{14}{1} \\\\ = 14 \end{array}$$

∴ Number of pieces = 14

6Exercise 2(B)

A log of wood $6\frac{2}{7}$m in length, was cut into 11 pieces. What is the length of each piece?

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Given :

Total length of a log of wood = $6\frac{2}{7}$ m = $\frac{44}{7}$ m

Number of pieces = 11

Length of each piece = ?

Length of each piece = (Total length of a log of wood) ÷ (Number of pieces)

Substituting the values in above, we get:

Length of each piece = $\frac{44}{7}$ m ÷ 11

$$\begin{array}{ll} = \Big(\frac{44}{7} \times \frac{1}{11}\Big)\text{ m} & [\text{Reciprocal of } 11 \text{ is } \frac{1}{11}] \\\\ = \Big(\frac{4}{7} \times \frac{1}{1}\Big)\text{ m} & \text{[Simplifying 44 and 11 ⇒ Divide by 11]} \\\\ = \frac{4}{7}\text{ m} \\\\ \end{array}$$

∴ The length of each piece = $\frac{4}{7}$ m

7Exercise 2(B)

A car covers $641\frac{1}{4}$km in $43\frac{1}{8}$ litres of fuel. How much distance can this car cover in 1 litre of fuel ?

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Given:

Total distance = $641\frac{1}{4}\text{ km} = \frac{2565}{4}$ km

Total fuel = $43\frac{1}{8}\text{ litres} = \frac{345}{8}\text{ litres}$

Distance per litre = ?

Distance per litre = (Total distance) ÷ (Total fuel)

Substituting the values in above, we get:

Distance per litre = $\frac{2565}{4}\text{ km} ÷ \frac{345}{8}\text{ litres}$

$$\begin{array}{ll} = \Big(\frac{2565}{4} \times \frac{8}{345}\Big)\text{ km} & [\text{Reciprocal of } \frac{345}{8} \text{ is } \frac{8}{345}] \\\\ = \Big(\frac{2565}{1} \times \frac{2}{345}\Big)\text{ km} & \text{[Simplifying 8 and 4 ⇒ Divide by 4]} \\\\ = \Big(\frac{171}{1} \times \frac{2}{23}\Big)\text{ km} & \text{[Simplifying 2565 and 345 ⇒ Divide by 15]} \\\\ = \frac{171 \times 2}{1 \times 23} \text{ km} \\\\ = \frac{342}{23} \text{ km} \\\\ = 14\frac{20}{23} \text{ km} \end{array}$$

∴ The distance per litre of petrol = $14\frac{20}{23}$ km

8Exercise 2(B)

The area of a rectangular plot of land is $817\frac{4}{5}$sq. m. If its breadth is $21\frac{3}{4}$m, find its length.

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Given:

Area of rectangular plot of land = $817\frac{4}{5}\text{ m}^2 = \frac{4089}{5}\text{ m}^2$

Breadth = $21\frac{3}{4}\text{ m} = \frac{87}{4} \text{ m}$

Length of rectangular plot of land = ?

Length of rectangular plot of land = (Area of rectangular plot of land) ÷ (Breadth)

Substituting the values in above, we get:

Length of rectangular plot of land = $\frac{4089}{5}\text{ m}^2 ÷ \frac{87}{4} \text{ m}$

$$\begin{array}{ll} = \Big(\frac{4089}{5} \times \frac{4}{87}\Big)\text{ m} & [\text{Reciprocal of } \frac{87}{4} \text{ is } \frac{4}{87}] \\\\ = \Big(\frac{47}{5} \times \frac{4}{1}\Big)\text{ m} & \text{[Simplifying 2565 and 345 ⇒ Divide by 15]} \\\\ = \frac{47 \times 4}{5 \times 1} \text{ m} \\\\ = \frac{188}{5} \text{ m} \\\\ = 37\frac{3}{5}\text{ m} \end{array}$$

∴ The breadth of rectangular plot of land = $37\frac{3}{5}$ m

9Exercise 2(B)

The area of a sheet of paper is $623\frac{7}{10}$ sq. cm. If its length is $29\frac{7}{10}$cm, find its width.

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Given:

Area of a sheet of paper = $623\frac{7}{10}\text{ cm}^2 = \frac{6237}{10}\text{ cm}^2$

Length = $29\frac{7}{10}\text{ cm} = \frac{297}{10}\text{ cm}$

Width = ?

The sheet of paper will be in rectangular shape,

∴ Area = Length x Width

Width = Area ÷ Length

Substituting the values in above, we get:

Width = $\frac{6237}{10}\text{ cm}^2$ ÷ $\frac{297}{10}\text{ cm}$

$$\begin{array}{ll} = \Big(\frac{6237}{10} \times \frac{10}{297}\Big)\text{ cm} & [\text{Reciprocal of } \frac{297}{10} \text{ is } \frac{10}{297}] \\\\ = \Big(\frac{6237}{1} \times \frac{1}{297}\Big)\text{ cm} & \text{[Simplifying 10 and 10 ⇒ Divide by 1]} \\\\ = \frac{6237 \times 1}{1 \times 297} \text{ cm} \\\\ = \frac{6237}{297}\text{ cm} \\\\ = 21 \text{ cm} \end{array}$$

∴ The width of a sheet of paper = 21 cm

10Exercise 2(B)

A bundle of 500 sheets of paper has a net weight of $2\frac{3}{10}$kg. Find the weight of 1 sheet of paper.

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Given:

Total weigth = $2\frac{3}{10} \text{ kg} = \frac{23}{10} \text{ kg}$

Number of sheets = 500

Weigth of 1 sheet of paper = (Total weigth) ÷ (Number of sheets)

Substituting the values in above, we get:

Weigth of 1 sheet of paper = $\frac{23}{10}$ kg ÷ 500

$$\begin{array}{ll} = \Big(\frac{23}{10} \times \frac{1}{500}\Big)\text{ kg} & [\text{Reciprocal of } 500 \text{ is } \frac{1}{500}] \\\\ = \frac{23 \times 1}{10 \times 500} \text{ kg} \\\\ = \frac{23}{5000} \text{ kg} \end{array}$$

∴ The weigth of 1 sheet of paper = $\frac{23}{5000}$ kg

11Exercise 2(B)

A car travels $283\frac{1}{2}$ km in $4\frac{2}{3}$ hours. How far does this car go in 1 hour, travelling at the same speed?

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Given:

Total distance = $283\frac{1}{2}\text{ km} = \frac{567}{2}\text{ km}$

Total time = $4\frac{2}{3}\text{ hours} = \frac{14}{3}\text{ hours}$

Distance covered in 1 hour = ?

Distance covered in 1 hour = (Total distance) ÷ (Total time)

Substituting the values in above, we get:

Distance covered in 1 hour = $\frac{567}{2}\text{ km} ÷ \frac{14}{3}\text{ hours}$

$$\begin{array}{ll} = \Big(\frac{567}{2} \times \frac{3}{14}\Big) \text{ km} & [\text{Reciprocal of } \frac{14}{3} \text{ is } \frac{3}{14}] \\\\ = \Big(\frac{81}{2} \times \frac{3}{2}\Big) \text{ km} & \text{[Simplifying 567 and 14 ⇒ Divide by 7]} \\\\ = \frac{81 \times 3}{2 \times 2}\text{ km} \\\\ = \frac{243}{4}\text{ km} \\\\ = 60\frac{3}{4}\text{ km} \end{array}$$

∴ The distance covered in 1 hour = $60\frac{3}{4}$ km

12Exercise 2(B)

The product of two fractions is $8\frac{7}{25}$. If one of them is $3\frac{1}{15}$ find the other.

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Given:

Let the two fractions be p and q.

p = $3\frac{1}{15} = \frac{46}{15}$

Let the other fraction be q.

p x q = $8\frac{7}{25} = \frac{207}{25}$

q = $\frac{207}{25}$ ÷ p $\hspace{2cm}\text{[Solving for q]}$

Substituting the value of p, we get:

q = $\frac{207}{25} ÷ \frac{46}{15}$

$$\begin{array}{ll} = \frac{207}{25} \times \frac{15}{46} & [\text{Reciprocal of } \frac{46}{15} \text{ is } \frac{15}{46}] \\\\ = \frac{207}{5} \times \frac{3}{46} & \text{[Simplifying 15 and 25 ⇒ Divide by 5]} \\\\ = \frac{9}{5} \times \frac{3}{2} & \text{[Simplifying 207 and 46 ⇒ Divide by 23]} \\\\ = \frac{9 \times 3}{5 \times 2} \\\\ = \frac{27}{10} \\\\ = 2\frac{7}{10} \end{array}$$

∴ The other fraction = $2\frac{7}{10}$

1Exercise 2(C)

Simplify :

$1\frac{2}{3} + \frac{5}{6}$ of $\frac{24}{25}$

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We have:

$1\frac{2}{3} + \frac{5}{6}$ of $\frac{24}{25}$

= $\frac{5}{3}$ + $\frac{5}{6}$ of $\frac{24}{25}$ [Converting mixed to improper fraction]

According to BODMAS rule, we solve "of" first

$$\begin{array}{ll} = \frac{5}{3} + \frac{5}{6} \times \frac{24}{25} \\\\ = \frac{5}{3} + \frac{1}{6} \times \frac{24}{5} \\\\ = \frac{5}{3} + \frac{24}{30} \\\\ = \frac{5}{3} + \frac{4}{5} & \text{[Of simplified]} \\\\ = \frac{25 + 12}{15} = \frac{37}{15} & \text{[Addition simplified]} \\\\ = 2\frac{7}{15} & \text{[Converting improper to mixed fraction]} \end{array}$$

∴ The answer is $2\frac{7}{15}$

2Exercise 2(C)

Simplify :

$\frac{1}{3}$ of $4\frac{2}{3} ÷ 2\frac{1}{3}\times 1\frac{1}{2}$

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We have:

$\frac{1}{3}$ of $4\frac{2}{3}$ ÷ $2\frac{1}{3}\times 1\frac{1}{2}$

= $\frac{1}{3}$ of $\frac{14}{3}$ ÷ $\frac{7}{3}\times \frac{3}{2}$ [Converting mixed to improper fraction]

According to BODMAS rule, we solve "of" first

$$\begin{array}{ll} = \frac{1}{3} \times \frac{14}{3} ÷ \frac{7}{3}\times \frac{3}{2} \\\\ = \frac{1 \times 14}{3 \times 3} ÷ \frac{7}{3}\times \frac{3}{2} \\\\ = \frac{14}{9} ÷ \frac{7}{3}\times \frac{3}{2} & \text{[Of simplified]} \\\\ = \frac{14}{9} \times \frac{3}{7}\times \frac{3}{2} & [\text{Reciprocal of } \frac{7}{3} \text{ is } \frac{3}{7}] \\\\ = \frac{14}{3} \times \frac{1}{7} \times \frac{3}{2} \\\\ = \frac{2}{3} \times \frac{1}{1} \times \frac{3}{2} \\\\ = \frac{2 \times1}{3 \times 1} \times \frac{3}{2} = \frac{2}{3} \times \frac{3}{2} & \text{[Division simplified]} \\\\ = \frac{2 \times 3}{3 \times 2} = \frac{6}{6}\\\\ = \frac{1}{1} = 1 & \text{[Multiplication simplified]} \end{array}$$

∴ The answer is 1

3Exercise 2(C)

Simplify :

$2\frac{1}{4} + 1\frac{1}{6} - 1\frac{2}{3} ÷ 2\frac{2}{3}$ of $3\frac{3}{4}$

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We have:

$2\frac{1}{4} + 1\frac{1}{6} - 1\frac{2}{3} ÷ 2\frac{2}{3}$ of $3\frac{3}{4}$

= $\frac{9}{4}$ + $\frac{7}{6}$ - $\frac{5}{3}$ ÷ $\frac{8}{3}$ of $\frac{15}{4}$ [Converting mixed to improper fraction]

According to BODMAS rule, we solve "of" first

$$\begin{array}{ll} = \frac{9}{4} + \frac{7}{6} - \frac{5}{3} ÷ \frac{8}{3}\times \frac{15}{4} \\\\ = \frac{9}{4} + \frac{7}{6} - \frac{5}{3} ÷ \frac{8 \times 15}{3 \times 4} \\\\ = \frac{9}{4} + \frac{7}{6} - \frac{5}{3} ÷ \frac{120}{12} \\\\ = \frac{9}{4} + \frac{7}{6} - \frac{5}{3} ÷ \frac{10}{1} & \text{[Of simplified]} \\\\ = \frac{9}{4} + \frac{7}{6} - \frac{5}{3} \times \frac{1}{10} & [\text{Reciprocal of } \frac{10}{1} \text{ is } \frac{1}{10}] \\\\ = \frac{9}{4} + \frac{7}{6} - \frac{5 \times 1}{3 \times 10} \\\\ = \frac{9}{4} + \frac{7}{6} - \frac{5}{30} \\\\ = \frac{9}{4} + \frac{7}{6} - \frac{1}{6} \\\\ = \frac{27 + 14}{12} - \frac{1}{6} \\\\ = \frac{41}{12} - \frac{1}{6} & \text{[Addition simplified]} \\\\ = \frac{41 - 2}{12} \\\\ = \frac{39}{12} \\\\ = \frac{13}{4} & \text{[Subtraction simplified]} \\\\ = 3\frac{1}{4} & \text{[Converting improper to mixed fraction]} \\\\ \end{array}$$

∴ The answer is $3\frac{1}{4}$

4Exercise 2(C)

Simplify :

$1\frac{1}{2}\times2\frac{3}{4} ÷ 1\frac{4}{7}$ of $2\frac{5}{8}$

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We have:

$1\frac{1}{2}\times2\frac{3}{4} ÷ 1\frac{4}{7}$ of $2\frac{5}{8}$

= $\frac{3}{2}\times \frac{11}{4}$ ÷ $\frac{11}{7}$ of $\frac{21}{8}$ [Converting mixed to improper fraction]

According to BODMAS rule, we solve "of" first

$$\begin{array}{ll} = \frac{3}{2}\times \frac{11}{4} ÷ \frac{11}{7} \times \frac{21}{8} \\\\ = \frac{3}{2}\times \frac{11}{4} ÷ \frac{11}{1} \times \frac{3}{8} \\\\ = \frac{3}{2}\times \frac{11}{4} ÷ \frac{11 \times 3}{1 \times 8} \\\\ = \frac{3}{2}\times \frac{11}{4} ÷ \frac{33}{8} & \text{[Of simplified]} \\\\ = \frac{3}{2}\times \frac{11}{4} \times \frac{8}{33} & [\text{Reciprocal of } \frac{33}{8} \text{ is } \frac{8}{33}] \\\\ = \frac{3}{2}\times \frac{1}{4} \times \frac{8}{3} \\\\ = \frac{3}{2}\times \frac{1}{1} \times \frac{2}{3}\\\\ = \frac{3}{2}\times \frac{1 \times 2}{1 \times 3} \\\\ = \frac{3}{2}\times \frac{2}{3} & \text{[Division simplified]} \\\\ = \frac{6}{6} = 1 & \text{[Multiplication simplified]} \\\\ \end{array}$$

∴ The answer is 1

5Exercise 2(C)

Simplify :

$\Big(2\frac{3}{4} + 1\frac{5}{6}\Big)$ ÷ $2\frac{1}{5}$ of $3\frac{1}{3}$

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We have:

$\Big(2\frac{3}{4} + 1\frac{5}{6}\Big)$ ÷ $2\frac{1}{5}$ of $3\frac{1}{3}$

= $\Big(\frac{11}{4} + \frac{11}{6}\Big)$ ÷ $\frac{11}{5}$ of $\frac{10}{3}$ [Converting mixed to improper fraction]

According to BODMAS rule, we simplify brackets first

$$\begin{array}{ll} = \Big(\frac{33 + 22}{12}\Big) ÷ \frac{11}{5} \text{ of } \frac{10}{3} \\\\ = \frac{55}{12} ÷ \frac{11}{5} \text{ of } \frac{10}{3} & \text{[Brackets simplified]} \\\\ = \frac{55}{12} ÷ \frac{11}{5} \times \frac{10}{3} \\\\ = \frac{55}{12} ÷ \frac{110}{15} \\\\ = \frac{55}{12} ÷ \frac{22}{3} & \text{[Of simplified]} \\\\ = \frac{55}{12} \times \frac{3}{22} & [\text{Reciprocal of } \frac{22}{3} \text{ is } \frac{3}{22}] \\\\ = \frac{5}{12} \times \frac{3}{2} & \text{[Dividing 55 and 22 by 11]} \\\\ = \frac{15}{24} = \frac{5}{8} & \text{[Division simplified]} \end{array}$$

∴ The answer is $\frac{5}{8}$

6Exercise 2(C)

Simplify :

$\frac{7}{15}$ of $\Big(\frac{2}{3} + \frac{7}{12}\Big)$ ÷ $\Big(\frac{5}{6}-\frac{3}{5}\Big)$

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We have:

$\frac{7}{15}$ of $\Big(\frac{2}{3} + \frac{7}{12}\Big)$ ÷ $\Big(\frac{5}{6}-\frac{3}{5}\Big)$

According to BODMAS rule, we simplify brackets first

$$\begin{array}{ll} = \frac{7}{15}\text{ of }\Big(\frac{8 + 7}{12}\Big) ÷ \Big(\frac{5}{6}-\frac{3}{5}\Big) \\\\ = \frac{7}{15}\text{ of } \Big(\frac{15}{12}\Big) ÷ \Big(\frac{5}{6}-\frac{3}{5}\Big) \\\\ = \frac{7}{15}\text{ of } \frac{15}{12} ÷ \Big(\frac{5}{6}-\frac{3}{5}\Big) & \text{[First bracket simplified]} \\\\ = \frac{7}{15}\text{ of } \frac{15}{12} ÷ \Big(\frac{25 - 18}{30}\Big) \\\\ = \frac{7}{15}\text{ of } \frac{15}{12} ÷ \frac{7}{30} & \text{[Second bracket simplified]} \\\\ = \frac{7}{15} \times \frac{15}{12} ÷ \frac{7}{30} \\\\ = \frac{7}{12} ÷ \frac{7}{30} & \text{[Of simplified]} \\\\ = \frac{7}{12} \times \frac{30}{7} & [\text{Reciprocal of } \frac{7}{30} \text{ is } \frac{30}{7}] \\\\ = \frac{1}{12} \times \frac{30}{1} & \text{[Dividing 7 and 7 by 7]} \\\\ = \frac{1}{2} \times \frac{5}{1} & \text{[Dividing 30 and 12 by 6]} \\\\ = \frac{5}{2} & \text{[Division simplified]} \\\\ = 2\frac{1}{2} \end{array}$$

∴ The answer is $2\frac{1}{2}$

7Exercise 2(C)

Simplify :

$\Big(22÷5\frac{1}{2}\Big)$ ÷ $2\frac{1}{5}$ of $3\frac{1}{3} + 1\frac{5}{11}$

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We have:

$\Big(22÷5\frac{1}{2}\Big)$ ÷ $2\frac{1}{5}$ of $3\frac{1}{3} + 1\frac{5}{11}$

= $\Big(22÷\frac{11}{2}\Big)$ ÷ $\frac{11}{5}$ of $\frac{10}{3}$ + $\frac{16}{11}$ [Converting mixed to improper fraction]

According to BODMAS rule, we simplify brackets first

$$\begin{array}{ll} = \Big(22 \times \frac{2}{11}\Big) ÷ \frac{11}{5}\text{ of }\frac{10}{3} + \frac{16}{11} & [\text{Reciprocal of } \frac{11}{2} \text{ is } \frac{2}{11}] \\\\ = \Big(\frac{44}{11}\Big) ÷ \frac{11}{5}\text{ of }\frac{10}{3} + \frac{16}{11} & \text{[Divide 44 and 11 by 11]} \\\\ = \frac{4}{1} ÷ \frac{11}{5}\text{ of }\frac{10}{3} + \frac{16}{11} & \text{[Bracket simplified]} \\\\ = \frac{4}{1} ÷ \frac{11}{5} \times \frac{10}{3} + \frac{16}{11} \\\\ = \frac{4}{1} ÷ \frac{110}{15} + \frac{16}{11} & \text{[Divide 110 and 15 by 5]} \\\\ = \frac{4}{1} ÷ \frac{22}{3} + \frac{16}{11} & \text{[Of simplified]} \\\\ = \frac{4}{1} \times \frac{3}{22} + \frac{16}{11} & [\text{Reciprocal of } \frac{22}{3} \text{ is } \frac{3}{22}] \\\\ = \frac{12}{22} + \frac{16}{11} & \text{[Divide 12 and 22 by 2]} \\\\ = \frac{6}{11} + \frac{16}{11} & \text{[Division simplified]} \\\\ = \frac{6 + 16}{11} = \frac{22}{11} & \text{[Divide 22 and 11 by 11]} \\\\ = 2 & \text{[Division simplified]} \end{array}$$

∴ The answer is 2

8Exercise 2(C)

Simplify :

$6\frac{1}{3}$ ÷ $\Big(2\frac{1}{5} + 3\frac{1}{2}\Big)$ of $3\frac{1}{3}$

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We have:

$6\frac{1}{3}$ ÷ $\Big(2\frac{1}{5} + 3\frac{1}{2}\Big)$ of $3\frac{1}{3}$

= $\frac{19}{3}$ ÷ $\Big(\frac{11}{5} + \frac{7}{2}\Big)$ of $\frac{10}{3}$ [Converting mixed to improper fraction]

According to BODMAS rule, we simplify brackets first

$$\begin{array}{ll} = \frac{19}{3} ÷ \Big(\frac{22 + 35}{10}\Big)\text{ of }\frac{10}{3} \\\\ = \frac{19}{3} ÷ \frac{57}{10}\text{ of }\frac{10}{3} & \text{[Bracket simplified]} \\\\ = \frac{19}{3} ÷ \frac{57}{10} \times \frac{10}{3} \\\\ = \frac{19}{3} ÷ \frac{570}{30} \\\\ = \frac{19}{3} ÷ \frac{19}{1} & \text{[Of simplified]} \\\\ = \frac{19}{3} \times \frac{1}{19} & [\text{Reciprocal of } \frac{19}{1} \text{ is } \frac{1}{19}] \\\\ = \frac{1}{3} & \text{[Division simplified]} \end{array}$$

∴ The answer is $\frac{1}{3}$

11 Mark · Multiple Choice Questions

Which of the following fractions can be expressed as a mixed fraction?

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A fraction can be expressed as a mixed fraction only if it is an improper fraction (numerator > denominator).

Hence, option 3 is the correct option.

21 Mark · Multiple Choice Questions

Which of the following is an improper fraction?

Show SolutionHide Solution↓

An improper fraction has numerator greater than denominator.

Hence, option 2 is the correct option.

31 Mark · Multiple Choice Questions

Three-fourths of 3 is

Show SolutionHide Solution↓

Given:

Three-fourths of 3

= $\frac{3}{4}$ of 3

= $\frac{3}{4} \times$ 3 = $\frac{9}{4}$

where numerator > denominator, therefore it is an improper fraction.

Hence, option 3 is the correct option.

41 Mark · Multiple Choice Questions

If the cost of a pen is ₹$16\frac{2}{3}$, then, the cost of 60 pens will be

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Given:

Cost of 1 pen = ₹$16\frac{2}{3}$

Number of pens = 60

Cost of 60 pens = ?

Cost of 60 pens = (Cost of 1 pen) x (Number of pens)

Substituting the values in above, we get:

Cost of 60 pens = ₹$16\frac{2}{3}$ x 60

= ₹$\frac{50}{3}$ x 60 = ₹$\frac{3000}{3}$ = ₹1000

Hence, option 4 is the correct option.

51 Mark · Multiple Choice Questions

If a sheet of paper having an area of $42\frac{1}{4}$ cm2 is cut into 13 strips of equal area, then the area of each strip will be

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Given:

Area of sheet = $42\frac{1}{4}$ cm2

Number of strips = 13

Area of each strip = ?

Area of each strip = (Area of sheet) ÷ (Number of strips)

Substituting the values in above, we get:

Area of each strip = $42\frac{1}{4}$ cm2 ÷ 13

$$\begin{array}{ll} = \frac{169}{4} \text{ cm}^2 ÷ 13 \\\\ = \Big(\frac{169}{4} \times \frac{1}{13}\Big) \text{ cm}^2 \\\\ = \Big(\frac{13}{4}\Big) \text{ cm}^2 \\\\ = 3\frac{1}{4} \text{ cm}^2 \end{array}$$

Hence, option 2 is the correct option.

1Mental Maths

Fill in the blanks :

(i) If $\frac{a}{b}$ is a fraction, then a and b are ............... .

(ii) In an improper fraction, the numerator is ............... the denominator.

(iii) The product of two improper fractions is a/an ............... fraction.

(iv) $\frac{a}{b}$ ÷ $\frac{c}{d}$ equal to the product of $\frac{a}{b}$ and ............... .

(v) The product of two proper fractions is ............... than each of the given fractions.

(vi) The reciprocal of a proper fraction is a/an ............... fraction.

(vii) The fraction whose reciprocal is equal to the fraction itself is ............... .

Show SolutionHide Solution↓

(i) If $\frac{a}{b}$ is a fraction, then a and b are natural numbers.

(ii) In an improper fraction, the numerator is greater than or equal to the denominator.

(iii) The product of two improper fractions is a/an improper fraction.

(iv) $\frac{a}{b}$ ÷ $\frac{c}{d}$ equal to the product of $\frac{a}{b}$ and the reciprocal of $\frac{c}{d}$.

(v) The product of two proper fractions is smaller than each of the given fractions.

(vi) The reciprocal of a proper fraction is a/an improper fraction.

(vii) The fraction whose reciprocal is equal to the fraction itself is 1 .

2Mental Maths

Write true (T) or false (F):

(i) In an improper fraction, the numerator is always greater than the denominator.

(ii) The product of two proper fractions can be an improper fraction.

(iii) Any improper fraction is always greater than any proper fraction.

(iv) Every unit fraction is equal to 1.

(v) The reciprocal of a proper fraction is an improper fraction.

(vi) The product of two proper fractions is always greater than each of the two proper fractions.

(vii) There exists a fraction whose multiplicative inverse is equal to the fraction itself.

(viii) The product of a proper fraction and and an improper fraction is always less than the improper fraction.

Show SolutionHide Solution↓

(i) False
Reason — In an improper fraction, the numerator may be equal to or greater than the denominator.

(ii) False
Reason — A proper fraction is less than 1. The product of two numbers less than 1 is always less than 1. Hence, it remains a proper fraction.

(iii) True
Reason — An improper fraction is greater than or equal to 1. A proper fraction is always less than 1. Therefore, any improper fraction is greater than any proper fraction.

(iv) False
Reason — A unit fraction is any fraction with a numerator of 1, such as $\frac{1}{5}, \frac{1}{9}$. Only the fraction $\frac{1}{1}$ is equal to 1.

(v) True
Reason — In a proper fraction, the denominator is larger than the numerator. When you take the reciprocal, the larger number becomes the numerator, making it an improper fraction.

(vi) False
Reason — The product of two proper fractions is always less than each of them.

(vii) True
Reason — The number 1 can be written as the fraction $\frac{1}{1}$. Its multiplicative inverse (reciprocal) is also $\frac{1}{1}$, which is equal to the original fraction. (Similarly, $-1$ or $\frac{-1}{1}$ also shares this property).

(viii) True
Reason — A proper fraction is less than 1. When a number is multiplied by a fraction less than 1, the product becomes smaller than the original number.

1Case Study Based Questions

When Prabhu Dayal died, he left all his money for his grand-children, 3 of whom were boys and 5 were girls. In his will he insisted that each grand-child must get equal share of the total amount of ₹56,00,000.

(1) What was the share of each child ?

  1. ₹8,00,000

  2. ₹11,20,000

  3. ₹6,40,000

  4. ₹7,00,000

(2) What fraction of the money did the girls receive ?

  1. $\frac{5}{3}$

  2. $\frac{3}{5}$

  3. $\frac{5}{8}$

  4. $\frac{3}{8}$

(3) How much did the boys receive in total ?

  1. ₹21,00,000

  2. ₹24,00,000

  3. ₹35,00,000

  4. ₹40,00,000

(4) If one of the girls did not take her share and the money is divided among the remaining grand-children, the fraction of the money received by the boys is :

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(1) Given:

Total Money = ₹56,00,000

Total Grand-children = 3 Boys + 5 Girls = 8 children

Each child receives equal share.

∴ Share of each child = Total Money ÷ Total Grand-children

Substituting the values in above, we get:

Share of each child = ₹56,00,000 ÷ 8

= ₹$\frac{5600000}{8}$ = ₹7,00,000

Hence, option 4 is the correct option.

(2) Given:

Number of girls = 5

Total children = 8

Fraction of money received by girls = Number of girls ÷ Total children

Substituting the values in above, we get:

Fraction of money received by girls = 5 ÷ 8

= $\frac{5}{8}$

Hence, option 3 is the correct option.

(3) Number of boys = 3

Given,

Amount received by each boy = ₹7,00,000 [From step 1]

Total amount received by boys = (Number of boys) x (Amount received by each boy)

Substituting the values in above, we get:

Total amount received by boys = 3 x ₹7,00,000

= ₹21,00,000

Hence, option 1 is the correct option.

(4) Given:

If one girl did not take her share,

Remaining children = 7 (3 boys + 4 girls)

Now total money is divided among 7 children equally.

Fraction received by boys = Number of boys ÷ Total children

Substituting the values in above, we get:

Fraction received by boys = 3 ÷ 7 = $\frac{3}{7}$

Hence, option 4 is the correct option.

2Case Study Based Questions

Amar is an electrician. He bought $7\frac{1}{2}$ bundles of an electric cable where each bundle had $202\frac{4}{5}$ m of cable.

(1) Find the total length of the cable purchased by Amar.

  1. 1427 m
  2. 1521 m
  3. 1605 m
  4. 1717 m

(2) If the cost of cable is ₹$6\frac{2}{3}$ per metre, find the amount paid by Amar.

  1. ₹8830
  2. ₹9520
  3. ₹10140
  4. ₹11280

(3) Amar used $2\frac{1}{2}$ bundles of cable for electric connections in the top floor of the building. What length of cable was used for the top floor ?

  1. 476 m
  2. 507 m
  3. 625 m
  4. 712 m

(4) Amar cut a length of $13\frac{4}{5}$m from a bundle and divided the remaining cable of this bundle into pieces of 21 m, length each. How many pieces of 21 m did he get from this bundle ?

Show SolutionHide Solution↓

(1) Given:

Total bundles = $7 \frac{1}{2} = \frac{15}{2}$

Length per bundle = $202 \frac{4}{5} = \frac{1014}{5}$ m

Total length of the cable purchased = (Total bundles) x (Length per bundle)

Substituting the values in above, we get:

Total length of the cable purchased = $\frac{15}{2}$ x $\frac{1014}{5}$ m

= $\frac{3}{2}$ x $\frac{1014}{1}$ m

= $\frac{3}{1}$ x $\frac{507}{1}$ m

= 1521 m

Hence, option 2 is the correct option.

(2) The cost of cable per meter = ₹$6\frac{2}{3} = ₹\frac{20}{3}$ $\hspace{2cm}$

Given

Total length of the cable = 1521 m $\hspace{2.5cm}$ [From previous step]

The amount paid by Amar = (Cost of cable per meter) x (Total length of the cable)

Substituting the values in above, we get:

The amount paid by Amar = ₹$\frac{20}{3}$ x 1521 m

= ₹20 x 507

= ₹10140

Hence, option 3 is the correct option.

(3) Given:

Bundles of cable used for the top floor = $2\frac{1}{2} = \frac{5}{2}$

Length per bundle = $\frac{1014}{5}$ m

Length of cable used for the top floor = (Bundles of cable used for the top floor) x (Length per bundle)

Substituting the values in above, we get:

Length of cable used for the top floor = $\frac{5}{2}$ x $\frac{1014}{5}$ m = 507 m

Hence, option 2 is the correct option.

(4) Given:

Length of one bundle = $\frac{1014}{5}$ m

Cut length = $13\frac{4}{5}$ m = $\frac{69}{5}$ m

Remaining length = (Length of one bundle - Cut length)

Substituting the values in above, we get:

Remaining length = $\Big(\frac{1014}{5} - \frac{69}{5}\Big)$ m

= $\frac{1014 - 69}{5}$ m = $\frac{945}{5}$ m = 189 m

Number of pieces of 21 m length = Remaining length ÷ 21

Substituting the values in above, we get:

Number of pieces of 21 m length = 189 m ÷ 21 = $\frac{189}{21}$

= 9

Hence, option 1 is the correct option.

1Assertions and Reasons

Assertion: Reciprocal of an improper fraction is a proper fraction.

Reason: Reciprocal is also known as multiplicative inverse.

Show SolutionHide Solution↓

Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).

Explanation

An improper fraction is a fraction where the numerator is greater than or equal to the denominator (e.g., $\frac{5}{3}$).

Its reciprocal is obtained by interchanging numerator and denominator:

$\frac{5}{3} \rightarrow \frac{3}{5}$

Since $\frac{3}{5}$ is less than 1, it is a proper fraction.

So, the Assertion is true.

The Reason is also true because reciprocal is indeed called the multiplicative inverse.

However, the reason does not explain why the reciprocal of an improper fraction becomes a proper fraction. It only defines what a reciprocal is.

Hence, option 2 is the correct option.

2Assertions and Reasons

Assertion: The product of two proper fractions is less than each of the fractions.

Reason: For any two fractions $\frac{a}{b}$ and $\frac{c}{b}$, we have, $\frac{a}{b} \times \frac{c}{b} = \frac{ac}{b}$.

Show SolutionHide Solution↓

Assertion (A) is true but Reason (R) is false.

Explanation

A proper fraction is less than 1.

When we multiply two numbers less than 1, the result becomes even smaller.

Example:

$\frac{1}{2} \times \frac{1}{3} = \frac{1}{6}$

$\frac{1}{6}$ is smaller than both $\frac{1}{2}$ and $\frac{1}{3}$

So, the Assertion is true.

The given formula in the Reason is incorrect.
Correct multiplication rule is:

$\frac{a}{b} \times \frac{c}{b} = \frac{ac}{bd}$

But the reason states the denominator remains b, which is wrong.

So, the Reason is false.

Hence, option 3 is the correct option.

1Competency Focused Questions

Find the product of P and Q, if the sum of numbers in each row and in each column is same.

$7\frac{3}{10}$$1\frac{1}{2}$$\frac{4}{5}$
$\frac{3}{5}$P$3\frac{7}{10}$
$1\frac{7}{10}$$2\frac{4}{5}$Q
Show SolutionHide Solution↓

Given:

The sum of numbers in each row and each column is the same.

First, we find the common sum by adding the numbers in the first row.

Sum of first row = $7\frac{3}{10} + 1\frac{1}{2} + \frac{4}{5}$

$$\begin{aligned}= \frac{73}{10} + \frac{3}{2} + \frac{4}{5} \\[1em] = \frac{73}{10} + \frac{15}{10} + \frac{8}{10} \hspace{1.5cm}\text{[Taking LCM = 10]} \\[1em] = \frac{73 + 15 + 8}{10} \\[1em] = \frac{96}{10}\end{aligned}$$

So, the common sum of each row and each column = $\frac{96}{10}$

Finding P (in the second column):

Sum of second column = $1\frac{1}{2}$ + P + $2\frac{4}{5}$ = $\frac{96}{10}$

$$\begin{aligned}\frac{3}{2} + P + \frac{14}{5} = \frac{96}{10} \\[1em] \frac{15}{10} + \frac{28}{10} + P = \frac{96}{10} \\[1em] \frac{43}{10} + P = \frac{96}{10} \\[1em] P = \frac{96}{10} - \frac{43}{10} \\[1em] P = \frac{53}{10}\end{aligned}$$

Finding Q (in the third row):

Sum of third row = $1\frac{7}{10}$ + $2\frac{4}{5}$ + Q = $\frac{96}{10}$

$$\begin{aligned}\frac{17}{10} + \frac{14}{5} + Q = \frac{96}{10} \\[1em] \frac{17}{10} + \frac{28}{10} + Q = \frac{96}{10} \\[1em] \frac{45}{10} + Q = \frac{96}{10} \\[1em] Q = \frac{96}{10} - \frac{45}{10} \\[1em] Q = \frac{51}{10}\end{aligned}$$

Finding the product P × Q:

$$\begin{aligned}P \times Q = \frac{53}{10} \times \frac{51}{10} \\[1em] = \frac{53 \times 51}{10 \times 10} \\[1em] = \frac{2703}{100} \\[1em] = 27\frac{3}{100}\end{aligned}$$

Hence, option 2 is the correct option.

2Competency Focused Questions

The value of

$\left(1 - \frac{1}{2}\right)\left(1 - \frac{1}{3}\right)\left(1 - \frac{1}{4}\right)............\left(1 - \frac{1}{10}\right) =$

Show SolutionHide Solution↓

We have:

$\left(1 - \frac{1}{2}\right)\left(1 - \frac{1}{3}\right)\left(1 - \frac{1}{4}\right)............\left(1 - \frac{1}{10}\right)$

Simplifying each bracket:

$$\begin{aligned}= \frac{2-1}{2} \times \frac{3-1}{3} \times \frac{4-1}{4} \times \frac{5-1}{5} \times \frac{6-1}{6} \times \frac{7-1}{7} \times \frac{8-1}{8} \times \frac{9-1}{9} \times \frac{10-1}{10} \\[1em] = \frac{1}{2} \times \frac{2}{3} \times \frac{3}{4} \times \frac{4}{5} \times \frac{5}{6} \times \frac{6}{7} \times \frac{7}{8} \times \frac{8}{9} \times \frac{9}{10} \\[1em] = \frac{1 \times 2 \times 3 \times 4 \times 5 \times 6 \times 7 \times 8 \times 9}{2 \times 3 \times 4 \times 5 \times 6 \times 7 \times 8 \times 9 \times 10} \hspace{1.5cm}\text{[Cancelling common terms]} \\[1em] = \frac{1}{10}\end{aligned}$$

Hence, option 3 is the correct option.

3Competency Focused Questions

How many more unit squares in the figure must be shaded so that the fraction of shaded squares is $\frac{7}{9}$?

How many more unit squares in the figure must be shaded so that the fraction of shaded squares is 7/9? Fractions, Foundation Mathematics R.S. Aggarwal ICSE Class 7.
Show SolutionHide Solution↓

From the figure:

Total number of unit squares = 18

Number of squares already shaded = 6

Required fraction of shaded squares = $\frac{7}{9}$

Number of squares that must be shaded = $\frac{7}{9}$ × 18 = 14

Number of more squares to be shaded = (Required shaded squares) − (Already shaded squares)

Substituting the values, we get:

Number of more squares to be shaded = 14 − 6 = 8

Hence, option 4 is the correct option.

4Competency Focused Questions

In a flower garden, $\frac{2}{10}$ are red roses, $\frac{5}{10}$ are pink roses and the rest are blue roses. What fraction of the roses are blue?

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Given:

Fraction of red roses = $\frac{2}{10}$

Fraction of pink roses = $\frac{5}{10}$

Total fraction of all roses = 1

Fraction of blue roses = 1 − (Fraction of red roses + Fraction of pink roses)

Substituting the values, we get:

$$\begin{aligned}\text{Fraction of blue roses} = 1 - \Big(\frac{2}{10} + \frac{5}{10}\Big) \\[1em] = 1 - \frac{2 + 5}{10} \\[1em] = 1 - \frac{7}{10} \\[1em] = \frac{10 - 7}{10} \\[1em] = \frac{3}{10}\end{aligned}$$

Hence, option 3 is the correct option.

5Competency Focused Questions

The following are the results from the class election.

The following are the results from the class election. If 150 students voted, about how many votes did Kumar receive? Fractions, Foundation Mathematics R.S. Aggarwal ICSE Class 7.

If 150 students voted, about how many votes did Kumar receive?

Show SolutionHide Solution↓

From the pie chart:

Reema occupies about half of the circle, i.e., $\frac{1}{2}$ of the total votes.

The remaining half is divided between Kumar and Manish, with Kumar's share being much larger than Manish's share.

Kumar's share is approximately $\frac{1}{3}$ of the total votes.

Total votes = 150

Number of votes received by Kumar = $\frac{1}{3}$ × 150

$$\begin{aligned}= \frac{1}{3} \times \frac{150}{1} \\[1em] = \frac{150}{3} \\[1em] = 50\end{aligned}$$

Hence, option 3 is the correct option.

6Competency Focused Questions

Anushka studied these pictures of fractions.

Anushka studied these pictures of fractions. What pattern might she correctly notice in the fractions? Fractions, Foundation Mathematics R.S. Aggarwal ICSE Class 7.

What pattern might she correctly notice in the fractions?

Show SolutionHide Solution↓

From the figure, the fractions shown are:

$\frac{2}{3}, \frac{2}{4}, \frac{2}{5}, \frac{2}{6}$

Observation:

The numerator remains the same (2) in all the fractions, while the denominator keeps increasing (3, 4, 5, 6).

As the denominator increases, the whole is divided into more parts, so each part becomes smaller. Hence, the value of the fraction decreases.

This is shown by the shaded regions in the circles, which keep getting smaller as we move from $\frac{2}{3}$ to $\frac{2}{6}$.

Hence, option 4 is the correct option.

7Competency Focused Questions

How many pieces of equal size can be cut from a rope of 30 m long, each measuring $3\frac{3}{4}$ m?

Show SolutionHide Solution↓

Given:

Total length of rope = 30 m

Length of each piece = $3\frac{3}{4}$ m = $\frac{15}{4}$ m

Number of pieces = (Total length of rope) ÷ (Length of each piece)

Substituting the values, we get:

Number of pieces = 30 ÷ $\frac{15}{4}$

$$\begin{aligned}= \frac{30}{1} \times \frac{4}{15} \\[1em] = \frac{2}{1} \times \frac{4}{1} \\[1em] = \frac{2 \times 4}{1 \times 1} \\[1em] = 8\end{aligned}$$

Hence, option 4 is the correct option.

8Competency Focused Questions

The value of $3 - \frac{1}{1 + \frac{2}{2 - \frac{3}{5}}}$ is:

Show SolutionHide Solution↓

We have:

$3 - \frac{1}{1 + \frac{2}{2 - \frac{3}{5}}}$

We simplify from the innermost fraction outwards.

Step 1: Simplify $2 - \frac{3}{5}$

$2 - \frac{3}{5} = \frac{10 - 3}{5} = \frac{7}{5}$

Step 2: Simplify $\frac{2}{2 - \frac{3}{5}} = \frac{2}{\frac{7}{5}}$

$\frac{2}{\frac{7}{5}} = 2 \times \frac{5}{7} = \frac{10}{7}$

Step 3: Simplify $1 + \frac{10}{7}$

$1 + \frac{10}{7} = \frac{7 + 10}{7} = \frac{17}{7}$

Step 4: Simplify $\frac{1}{1 + \frac{2}{2 - \frac{3}{5}}} = \frac{1}{\frac{17}{7}}$

$\frac{1}{\frac{17}{7}} = 1 \times \frac{7}{17} = \frac{7}{17}$

Step 5: Simplify $3 - \frac{7}{17}$

$3 - \frac{7}{17} = \frac{51 - 7}{17} = \frac{44}{17}$

Hence, option 4 is the correct option.

9Competency Focused Questions

Which of the following represents the shaded parts?

Which of the following represents the shaded parts? Fractions, Foundation Mathematics R.S. Aggarwal ICSE Class 7.
Show SolutionHide Solution↓

From the figure:

First triangle:

The triangle is divided into 4 equal smaller triangles. Out of these, only 1 (the central inverted) triangle is shaded.

So, fraction of shaded portion = $\frac{1}{4}$

Second triangle:

The triangle is divided into 4 equal smaller triangles. Out of these, 3 triangles (the corners) are shaded.

So, fraction of shaded portion = $\frac{3}{4}$

Total shaded fraction = $\frac{1}{4} + \frac{3}{4}$

Hence, option 4 is the correct option.

10Competency Focused Questions

What is the least fraction that must be added to $\left(1\frac{1}{3} \times 1\frac{1}{2}\right) \div 1\frac{1}{9}$ to make the result a natural number?

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We have:

$\left(1\frac{1}{3} \times 1\frac{1}{2}\right) \div 1\frac{1}{9}$

$$\begin{aligned}= \Big(\frac{4}{3} \times \frac{3}{2}\Big) \div \frac{10}{9} \\[1em] = \frac{4 \times 3}{3 \times 2} \div \frac{10}{9} \\[1em] = \frac{12}{6} \div \frac{10}{9} \\[1em] = 2 \div \frac{10}{9} \hspace{1.5cm}\text{[Bracket simplified]} \\[1em] = 2 \times \frac{9}{10} \hspace{1.5cm}\text{[Reciprocal of } \frac{10}{9} \text{ is } \frac{9}{10}] \\[1em] = \frac{18}{10} \\[1em] = \frac{9}{5}\end{aligned}$$

To make the result a natural number, we must add the least fraction that takes $\frac{9}{5}$ to the next natural number.

The next natural number greater than $\frac{9}{5}$ is 2.

Required least fraction = 2 − $\frac{9}{5}$

$$\begin{aligned}= \frac{10 - 9}{5} \\[1em] = \frac{1}{5}\end{aligned}$$

Hence, option 2 is the correct option.

11Competency Focused Questions

I read $\frac{4}{9}$ of a book on one day and $\frac{3}{5}$ of the remaining next day. If 100 pages of the book were still left unread, how many pages did the book contain?

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Given:

Let the total number of pages in the book = x

Day 1:

Pages read on day 1 = $\frac{4}{9}$ of x = $\frac{4x}{9}$

Remaining pages after day 1 = x − $\frac{4x}{9}$ = $\frac{9x - 4x}{9}$ = $\frac{5x}{9}$

Day 2:

Pages read on day 2 = $\frac{3}{5}$ of remaining = $\frac{3}{5} \times \frac{5x}{9}$

$$\begin{aligned}= \frac{3 \times 5x}{5 \times 9} \\[1em] = \frac{15x}{45} \\[1em] = \frac{x}{3}\end{aligned}$$

Pages remaining after day 2 = $\frac{5x}{9} - \frac{x}{3}$

$$\begin{aligned}= \frac{5x}{9} - \frac{3x}{9} \hspace{1.5cm}\text{[Taking LCM = 9]} \\[1em] = \frac{5x - 3x}{9} \\[1em] = \frac{2x}{9}\end{aligned}$$

According to the question, pages still left unread = 100

$$\begin{aligned}\frac{2x}{9} = 100 \\[1em] 2x = 100 \times 9 \\[1em] 2x = 900 \\[1em] x = \frac{900}{2} \\[1em] x = 450\end{aligned}$$

Hence, option 1 is the correct option.

12Competency Focused Questions

A drum of petrol is $\frac{3}{4}$ full. When 30 litres of oil are drawn from it, it is $\frac{7}{12}$ full. The capacity of the drum is:

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Given:

Let the capacity of the drum = x litres

Initial petrol in drum = $\frac{3}{4}$ of x = $\frac{3x}{4}$ litres

Petrol drawn out = 30 litres

Final petrol in drum = $\frac{7}{12}$ of x = $\frac{7x}{12}$ litres

According to the question:

Initial petrol − Petrol drawn out = Final petrol

Substituting the values, we get:

$$\begin{aligned}\frac{3x}{4} - 30 = \frac{7x}{12} \\[1em] \frac{3x}{4} - \frac{7x}{12} = 30 \\[1em] \frac{9x - 7x}{12} = 30 \hspace{1.5cm}\text{[Taking LCM = 12]} \\[1em] \frac{2x}{12} = 30 \\[1em] \frac{x}{6} = 30 \\[1em] x = 30 \times 6 \\[1em] x = 180\end{aligned}$$

So, the capacity of the drum = 180 litres

Hence, option 2 is the correct option.

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