Question

A number first increases by 30% and then decreases by 20%. Find the percent increase or decrease on the whole.​

Answer 1

Answer: PERCENTAGE INCREASE: (30-20)/20 = 10/20 = 1/2 = 0.5 = 50%.

Let the original price be x

Then increased to 20%⟹x+

100

20

x=

5

6

x

Then decreased to 30%⟹

5

6

x−

100

30

×

5

6

x=

25

21

x

So the net decrease is x−

25

21

x=

25

4

x

The percentage change is

x

25

4

x

×100=16%