Punjab State Board PSEB 7th Class Maths Book Solutions Chapter 2 Fractions and Decimals Ex 2.4 Textbook Exercise Questions and Answers.

## PSEB Solutions for Class 7 Maths Chapter 2 Fractions and Decimals Ex 2.4

1. Find the reciprocal of each of the following fraction.

(i) \(\frac {2}{7}\)

(ii) \(\frac {3}{2}\)

(iii) \(\frac {5}{7}\)

(iv) \(\frac {1}{9}\)

(v) \(\frac {2}{3}\)

(vi) \(\frac {7}{8}\)

Answer:

(i) \(\frac {7}{2}\)

(ii) \(\frac {2}{3}\)

(iii) \(\frac {7}{5}\)

(iv) 9

(v) \(\frac {3}{2}\)

(vi) \(\frac {8}{7}\)

2. Solve the following (Division of a fraction by a non zero whole number)

Question (i).

\(\frac {19}{6}\) ÷ 10

Answer:

\(\frac {19}{6}\) ÷ 10

= \(\frac{19}{6} \times \frac{1}{10}\)

= \(\frac {19}{60}\)

Question (ii).

\(\frac {4}{9}\) ÷ 5

Answer:

\(\frac {4}{9}\) ÷ 5

= \(\frac{4}{9} \times \frac{1}{5}\)

= \(\frac {4}{45}\)

Question (iii).

\(\frac {8}{9}\) ÷ 8

Answer:

\(\frac {8}{9}\) ÷ 8

= \(\frac{8}{9} \times \frac{1}{8}\)

= \(\frac {1}{9}\)

Question (iv).

3\(\frac {1}{2}\) ÷ 4

Answer:

3\(\frac {1}{2}\) ÷ 4

= \(\frac{7}{2} \times \frac{1}{4}\)

= \(\frac {7}{8}\)

Question (v).

16\(\frac {1}{2}\) ÷ 5

Answer:

16\(\frac {1}{2}\) ÷ 5

= \(\frac{33}{2} \times \frac{1}{5}\)

= \(\frac {33}{10}\)

= 3\(\frac {3}{10}\)

Question (vi).

4\(\frac {1}{3}\) ÷ 3

Answer:

4\(\frac {1}{3}\) ÷ 3

= \(\frac{13}{3} \times \frac{1}{3}\)

= \(\frac {33}{9}\)

= 1\(\frac {4}{9}\)

3. Solve the following (Division of a whole number by a fraction)

Question (i).

8 ÷ \(\frac {7}{3}\)

Answer:

8 ÷ \(\frac {7}{3}\)

= 8 × \(\frac {3}{7}\)

= \(\frac {24}{7}\)

= 3\(\frac {3}{7}\)

Question (ii).

5 ÷ \(\frac {7}{5}\)

Answer:

5 ÷ \(\frac {7}{5}\)

= 5 × \(\frac {5}{7}\)

= \(\frac {25}{7}\)

= 3\(\frac {4}{7}\)

Question (iii).

4 ÷ \(\frac {8}{3}\)

Answer:

4 ÷ \(\frac {8}{3}\)

= 4 × \(\frac {3}{8}\)

= \(\frac {3}{2}\)

= 1\(\frac {1}{2}\)

Question (iv).

3 ÷ 2\(\frac {3}{5}\)

Answer:

3 ÷ 2\(\frac {3}{5}\)

= 3 ÷ \(\frac {13}{5}\)

= 3 × \(\frac {5}{13}\)

= \(\frac {15}{13}\)

= 1\(\frac {2}{13}\)

Question (v).

5 ÷ 3\(\frac {4}{7}\)

Answer:

5 ÷ 3\(\frac {4}{7}\)

= 5 ÷ 3\(\frac {25}{7}\)

= 5 × \(\frac {7}{25}\)

= \(\frac {7}{25}\)

= 1\(\frac {2}{5}\)

4. Solve the following (Division of a fraction by another fraction)

Question (i).

\(\frac{2}{3} \div \frac{10}{9}\)

Answer:

\(\frac{2}{3} \div \frac{10}{9}\)

= \(\frac{2}{3} \times \frac{9}{10}\)

= \(\frac {3}{5}\)

Question (ii).

\(\frac{4}{9} \div \frac{2}{3}\)

Answer:

\(\frac{4}{9} \div \frac{2}{3}\)

= \(\frac{4}{9} \times \frac{3}{2}\)

= \(\frac {2}{3}\)

Question (iii).

\(2 \frac{1}{2} \div \frac{3}{5}\)

Answer:

\(2 \frac{1}{2} \div \frac{3}{5}\)

= \(\frac{5}{2} \times \frac{5}{3}\)

= \(\frac {25}{6}\)

= 4\(\frac {1}{6}\)

Question (iv).

\(\frac{3}{7} \div 1 \frac{1}{5}\)

Answer:

\(\frac{3}{7} \div 1 \frac{1}{5}\)

= \(\frac{3}{7} \div \frac{6}{5}\)

= \(\frac{3}{7} \times \frac{5}{6}\)

= \(\frac {5}{14}\)

Question (v).

\(5 \frac{1}{2} \div 2 \frac{1}{5}\)

Answer:

\(5 \frac{1}{2} \div 2 \frac{1}{5}\)

= \(\frac{11}{2} \div \frac{11}{5}\)

= \(\frac{11}{2} \times \frac{5}{11}\)

= \(\frac {5}{2}\)

= 2\(\frac {1}{2}\)

Question (vi).

\(3 \frac{1}{5} \div 1 \frac{2}{3}\)

Answer:

\(3 \frac{1}{5} \div 1 \frac{2}{3}\)

\(\frac{16}{5} \div \frac{5}{3}\)

= \(\frac{16}{5} \times \frac{3}{5}\)

= \(\frac {48}{25}\)

= 1\(\frac {23}{25}\)

5. 11 small ropes are cut from 7\(\frac {1}{3}\) m long rope. Find the length of each of the small rope.

Solution:

Length of rope = 7\(\frac {1}{3}\) m = \(\frac {22}{3}\) m,

∴ Length of 11 small ropes = \(\frac {22}{3}\)m

Length of each small rope = \(\frac {22}{3}\)m ÷ 11

= \(\frac{22}{3} \times \frac{1}{11} \mathrm{~m}\)

= \(\frac {2}{3}\)m

6. Multiple choice questions :

Question (i).

Reciprocal of \(\frac {3}{4}\) is :

(a) \(\frac {3}{4}\)

(b) \(\frac {4}{3}\)

(c) 1

(d) none of these

Answer:

(b) \(\frac {4}{3}\)

Question (ii).

\(\frac{5}{7} \div \frac{7}{5}=?\)

(a) 1

(b) \(\frac {49}{25}\)

(c) \(\frac {25}{49}\)

(d) -1

Answer:

(c) \(\frac {25}{49}\)

Question (iii).

\(\frac{5}{7} \div \frac{5}{7}=?\)

(a) 1

(b) \(\frac {49}{25}\)

(c) \(\frac {25}{49}\)

(d) -1

Answer:

(a) 1

7.

Question (i).

The reciprocal of a proper fraction is an improper fraction (True/False)

Answer:

True

Question (ii).

The reciprocal of a whole number is always a whole number (True / False)

Answer:

False.