**Chapter 8 Comparing Quantities Exercise 8.1**

Question 1.

Find the ratio of the following:

(a) speed of a cycle 15 km per hour to the speed of scooter 30 km per hour.

(b) 5 m to 10 km

(c) 50 paise to ₹ 5

Solution:

(a) Speed of cycle : Speed of Scooter = 15 km per hour : 30 km per hour

Hence, the ratio = 1 : 2

(b) 5 m to 10 km

= 5 m : 10 × 1000 m [∵ 1 km = 1000 m]

= 5 m : 10000 m

= 1 : 2000

Hence, the ratio = 1 : 2000

(c) 50 paise to ₹ 5

= 50 paise : 5 × 100 paise

= 50 paise : 500 paise

ratio = 1 : 10.

Question 2.

Convert the following ratios to percentages:

(a) 3 : 4

(b) 2 : 3

Solution :

Question 3.

72% of 25 students are good in mathematics. How many are not good in mathematics?

Solution:

Number of students who are good in mathematics = 72% of 25

Number of students who are not good in mathematics = 25 – 18 = 7