Chapter 8 Comparing Quantities Exercise 8.2

Question 1.
Convert the given fractional numbers to per cents:


Solution:



Question 2.
Convert the given decimal fractions to per cents:
(а) 0.65
(b) 2.1
(c) 0.02
(d) 12.35
Solution:

Question 4.
Find:
(a) 15% of 250
(b) 1% of 1 hour
(c) 20% of ₹ 2500
(d) 75% of 1 kg
Solution:

(b) 1% of 1 hour = 1% of 60 minutes [∵ 1 h = 60 min.]
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.2 9

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

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:
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.2 16

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%

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.

NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.2 Q1
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.2 Q2
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.2 Q3
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NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.2 Q5
NCERT Solutions for Class 7 Maths Chapter 8 Comparing Quantities Ex 8.2 Q6
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