Question

Two numbers X and Y are respectively 20% and
28% less than a third number Z. By what
percentage is the number Y less than the number
X?
(a) 12%
(c) 9%
(b) 10%
(d) 8%
​

Answer 1

Given : Two numbers x and y are respectively 20% and 28% less than a third number z.
To Find: by what percentage is the number y less than that of the number x?
Solution :
We are given two numbers x and y
Since x is 20% less than z
⇒x = z-20% ---1
Since y is 28% less than z
⇒y = z-28%----2
Subtract 1 from 2
⇒y-x = z-28% -(z-20%)
⇒y-x = z-28%-z+20%
⇒y-x = -8%
⇒y = x-8%
Thus y is 8 % less than x.