Haryana State Board HBSE 7th Class Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 Textbook Exercise Questions and Answers.

## Haryana Board 7th Class Maths Solutions Chapter 8 Comparing Quantities Exercise 8.2

Question 1.

Convert the given fractional number to per cents.

(a) \(\frac{1}{8}\)

(b) \(\frac{5}{4}\)

(c) \(\frac{3}{40}\)

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

Solution:

Question 2.

Convert the given decimal fractions to per cents.

(a) 0.65

(b) 2.1

(c) 0.02

(d) 12.35

Solution:

Question 3.

Estimate what part of the figures is coloured and hence find the per cent which is coloured.

Solution:

(j) Percentage of coloured part

= \(\frac{1}{4}\) × 100% = 25%

(ii) Percentage of coloured part

= \(\frac{3}{5}\) × 100% = 60%

(iii) Percentage of coloured part

= \(\frac{3}{8}\) × 100% = 37\(\frac{1}{2}\)%

Question 4.

Find :

(а) 15% of 250

(b) 25% of 150

(c) 1% of 1 hour

(d) 20% of Rs. 2500

(e) 75% of 1 kg.

Solution:

Question 5.

Find the whole quantity if:

(a) 5% of it is 600

(b) 12% of it is Rs. 1080

(c) 40% of it is 500 km.

(d) 70% of it is 14 mins.

Solution:

(a) Hence, 5% of x = 600

\(\frac{5}{100}\) × x — 600

or \(\frac{x}{20}=\frac{600}{1}\)

or, x = 20 × 600

∴ x = 12000.

(b) 12% of x = 1080

or, \(\frac{12}{100}\) × x = 1080

or, 12x = 1080 × 100

or, x = \(\frac{1080 \times 100}{12}\)

∴ x = Rs. 9000

(c) 40% of x = 500

or, \(\frac{40}{100}\) × x = 50

or, 2x = 5 × 500

or x = \(\frac{5 \times 500}{2}\)

100 = 500

or, 2x = 5 × 500

or, x = \(\frac{5 \times 500}{2}\)

∴ x = 1250 km.

(d) 70% of x = 14 mins.

or, \(\frac{70}{100}\) × x = 14

or, 7x = 14 × 10

or x = \(\frac{14 \times 10}{7}\)

x = 20 mins.

(e) 8% of × 8 = 40 litres 40

or, \(\frac{8}{100}\) × x = 40

or, 2x = 40 × 25

or, x = \(\frac{40 \times 25}{2}\)

x = 500 litres.

Question 6.

Convert given per cents to decimals and also to fractions in simplest forms :

(a) 25%

(b) 150%

(c) 20%

(d) 5%

Solution:

Question 7.

In a city, 30% are females, 40% are males and remaining are children. What per cent are children ?

Solution:

Percent of children

= [100 – (30 + 40)]%

= (100 – 70)% = 30%

Question 8.

Out of 15,000 voters in a constituency, 60% voted. Find the percentage of voters who did not vote. Can you now find how many actually did not vote?

Solution:

Percent of vote = 60%

Percent of not vote = (100 – 60)%

= 40%

No. of actually did not vote

= 40% of 15000 = \(\frac{40}{100}\) × 15000 = 6000

Question 9.

Meeta saves Rs. 400 from her salary. If this is 10% of her salary. What is her salary ?

Solution:

Let her salary be Rs. x.

Hence, 10% of x = 400

or \(\frac{10}{100}\) × x = 400

or x = 400 × 10

= Rs. 4000

Question 10.

A local cricket team played 20 matches in one season. It won 25% of them. How many matches did they win ?

Solution:

No. of total match = 20

percentage of won match = 25%

∴ Total number of winning match

= 20 of 25% = 20 × \(\frac{25}{100}\) = 5