Question

a man salary was raised by 10% and then reduced by 10% find the percentage change in his salary

Answer 1

first increased by 10% and then decreased by 10%

let her salary be 100

10% = 10/100 = 1/10

so 10% of 100 = 10

new salary after increase= 100 + 10 = 110..

now 10% of 110 is 11

so new salary after decrease is 110 -11 = 99

1 loss on 100 means 1%

OR

20 =1/5 means 20% of 5 = 1

similarly 25% = 1/4 means 25 percent of 4 is 1

10% = 1/10 .. 10 percent of 10 is 1

10% increase means

initial salary was 10 now its 11(10+1)..[1 is 10% of 10 as explained above]

10 % decrease means initial salary was 10 new is 9 (10–1)

now its like

initial salary new salary

10 11

10 9

100 99 [ 10*10 11*9]

loss of 1 over 100 means 1%

OR

[x + y +xy/100]%

10 + (-10) + (10)(-10)/100

-100/100 = -1%

Answer 2

Let the salary be 100

Salary raised by 10%=100+100/10=110

Salary reduced by 10%=110-110×10/100=110-10=99

So, 100-99=1

Percentage change=1×100/100=1%(Ans)