Question

Amit was given an increment of 25% on his salary. if his new salary is rs 20000 what was his salary before the increment

Answer 1

Let the initial salary be y.
now if we increase y by 25%,
 the value will become 32000.
It's equation is given as,   
 y+25%xy=32000(we can also write 25% as 25/100)
 soy+(25/100)y=32000taking
 L.C.M. of y+(25/100)y we get,
(125/100)y=3200
now we take (125/100) to the other side of equation,
 it becomes its reciprocal as
,y=3200x(100/125)y=25600
So his original salary was Rs.25600.

Answer 2

Increment: 25%
25% = 25/100 = 1/4
New salary(after increment) = 20,000
25%---1/4 ..[if '4' parts be old salary, 25% of '4' = 1,hence new=4+1=5]
4(old salary)-------5(new salary)
Given, 5 parts = 20,000
           1 part  = 20,000/5 = 4,000
           4 parts = 4*4000 = 16,000 Rs.
Hence his salary before increment was Rs.16,000
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Alternatively:
Let his actual salary be 'X'
Increment = 25%
New salary = 20,000
X*125/100 = 20,000
X*5/4 = 20,000
X= 4*20000/5 = 16,000 Rs.
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Hope it helps