### NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.2

**Ex 8.2 Class 7 Maths Question 1.**

**Convert the given fractional numbers to per cents:**

**Solution:**

**Ex 8.2 Class 7 Maths Question 2.**

**Convert the given decimal fractions to per cents:**

**(а) 0.65**

**(b) 2.1**

**(c) 0.02**

**(d) 12.35**

**Solution:**

**
**(a) 0.65 = 0.65 × 100/100 = 0.65 × 100% = 65%

(b) 2.1 = 2.1 × 100/100 = 2.1 ×100% = 210%

(c) 0.02 = 0.02 × 100/100 = 0.02 × 100% = 2%

(d) 12.35 = 12.35 × 100/100 = 12.35 × 100% = 1235%

**Ex 8.2 Class 7 Maths Question 3.**

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

**Solution:**

(i) Fraction of coloured part = 1/4

∴ Percentage of coloured parts 100

(ii) Fraction of coloured part = 3/6

∴ Percentage of coloured parts

(iii) Fraction of coloured part = 6/8

∴ Percentage of coloured parts

**Ex 8.2 Class 7 Maths Question 4.**

**Find:**

**(a) 15% of 250**

**(b) 1% of 1 hour**

**(c) 20% of ₹ 2500**

**(d) 75% of 1 kg**

**Solution:**

(a) 15% of 250 = 15/100 × 250 = 75/2 = 37.5

(b) 1% of 1 hour = 1% of 60 minutes [∵ 1 h = 60 min.]

**Ex 8.2 Class 7 Maths Question 5.**

**Find the whole quantity if**

**(a) 5% of it is 600**

**(b) 12% of it is? 1080**

**(c) 40% of it is 500 km**

**(d) 70% of it is 14 minutes**

**(e) 8% of it is 40 litres**

**Solution:**

Let the required whole quantity be x.

(a) 5% of x = 600

Thus the required whole quantity is 12,000.

(b) 12% of x = ₹ 1080

Thus, the required quantity is ₹ 9,000.

(c) 40% of x = 500 km

Thus, the required quantity = 1250 km.

(d) 70% of x = 14 minutes

Thus, the required quantity = 20 minutes,

(e) 8% of x = 40 litre 8

Thus, the required quantity = 500 litres

**Ex 8.2 Class 7 Maths Question 6.**

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

**(a) 25%**

**(b) 150%**

**(c) 20%**

**(d) 5%**

**Solution:**

**Ex 8.2 Class 7 Maths Question 7.**

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

**Solution:**

Given: 30% are females

40% are males

Total Percentage of females and males

= 30% + 40% = 70%

∴ Percentage of children

= (100 – 70)% = 30%

**Ex 8.2 Class 7 Maths 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:**

Total number of voters = 15,000

Percentage of the voters who voted = 60%

∴ Percentage of the voters who did not vote

= (100 – 60)% = 40%

Actual number of voters who did not vote

= 40% of 15,000

= 40/100 × 15,000 = 6,000

**Ex 8.2 Class 7 Maths Question 9.**

**Meena saves ₹ 400 from her salary. If this is 10% of her salary. What is her salary?**

**Solution:**

Let Meena’s salary by ₹ x.

∴ 10% of x = ₹ 400

Thus, her salary is ₹ 4000.

**Ex 8.2 Class 7 Maths Question 10.**

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

**Solution:**

Number of matches played by the cricket team = 20

Percentage of the matches won by them = 25%

i.e. 25/100 × 20 = 5 matches

Thus, the number of matches won by them = 5