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Expressing a Quantity as Percentage of Another Quantity

1. The units of both quantities should be same.
2. Form the fraction with the number to be compared as the numerator and the number with
which it is to be compared as the denominator.

3. Multiply the above fraction by 100.
Example 12: Express: Think and Answer

(a) 180 as the percentage of 600 1. Find 64% of a number if 18%
of the number is 360.
(b) 80 cm as the percentage of 2 m 40 cm 2. If x% of y = z, find the value of

(c) 27 min as the percentage of 2 hr 15 min x if y = 20 and z = 4.
Solution: (a) 180 as the percentage of 600

 180  180
=  600 × 100 % = 6 % = 30%



(b) 80 cm as the percentage of 2 m 40 cm
 80cm   80cm   1  1
3
=  240cm × 100 % =  240cm × 100 % =  3 × 100 % = 33 %









3
m
(c) 27 min as the percentage of 2 hr 15 min
 27 min   27 min 
=  2hr 15min × 100 % =  135min × 100 %






 1 
=  5 × 100 % = 20%



Example 13: What per cent of 60 m is 18m?
Solution: Let x% of 60 m is 18 m
 x 

 100 × 60 = 18


3x = 18
5
×
18 5
x = = 30%
3
\ 30% of 60 m is 18 m.
Example 14: What per cent of `1 is 25 paise?
Solution: Let x % of 100 paise = 25 paise [`1 = 100]
x
× 100 = 25
100

x = 25%
Thus, 25 paise is the 25% of `1.

225 Percentage and Its Applications