Class 8 Maths Comparing Quantities Introduction:

Introduction:

In our daily life, we handle lots of situations, quantities, etc. Sometimes we have to measure and

compare these quantities. The comparison is a common activity among us. Sometimes we compare our

height, sometimes marks, sometimes speed, sometimes distance, and so many.

A ratio is a comparison between two or more like quantities in the same units.

Ex: If we compare 10 mangoes with 25 mangoes, we write 10 : 25 or 10/25 = 2/5

In terms of ratio, 2 : 5 is read as “2 is to 5”

Problem: 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) 50 m to 10 km                             (c) 50 paise to ₹ 5

Solution:

(a) Speed of cycle = 15 km/hr

Speed of scooter = 30 km/hr

Hence ratio of speed of cycle to that of scooter = 15 : 30

= 15/30

= 1/2 = 1 : 2

(b) Since 1 km = 1000 m

So, 10 km = 10 * 1000 = 10000 m

Now, Ratio = 5 m/10000 m = 1/2000 = 1 : 2000

(c) Since ₹ 1 = 100 paise

So, ₹ 5 = 5 * 100 = 500 paise

Hence Ratio = 50 paise/500 paise = 1/10 = 1 : 10

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