Question

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

Answer 1

Answer:

4% decrease

Step-by-step explanation:

let the no. be '100'

20÷100×100=20

therefore, increase = 100 + 20= 120

20÷100×120=24

therefore, decrease =120 - 24 = 96

thus, decrease on total = 100 - 96/100x100

= 100 - 96

= 4 percent decrease

Answer 2

Answer:

4% Decrease.

Given:

A number first increases by 20% and then decreases by 20%.

To find:

Increase or decrease percent on the whole.

Solution:

Let the number be 100.

Now, 100 is increased by 20% = 20/100×100

=> 20

New number after 20% increase = 100+20 = 120.

Now, 120 is decreased by 20%.= 20/100×120

=> 24

New number after 20% Decrease = 120-24 = 96

Total decrease on whole = 24-20

=> 4

Total decrease % on whole 4/100×100

=> 4%