Question

a number is increased by 20% and then decreased by 20% . find the net increased or decrease percentage

Answer 1

If a no. Is first increased by a% and

then by b%,then net increase in %

=[a+b+(ab)/100]%

For this question a=20,and b=20

Net increase=[20+20+(20×20)/100]%

=(40+4)%=44%.

Hope it helps

Answer 2

Let the number be 100 %
It is given that first the number is increased by 20 %
Hence, 20 % of 100 % = (20/100) x (100/100)
= 20/100
= 20 %
So, increase in number = 100 % + 20 %
= 120 %
Also given that the number is decreased by 20 %
Hence, 20 % of 120 % = (20/100) x (120/100)
= 24/100
= 24 %
So, decrease in number = 120 % - 24 %
= 96 %
which shows that the net decrease in percent of the original number is 4%