20% is the change from 40 to 48
Calculation steps:
[( 48 - 40 ) ÷ 40] x 100 = 20%
Formula
Percentage change = [(48 - 40) / 40] x 100
Subtract the new number by the original number
48 - 40 = 8
8 ÷ 40 = 0.2
0.2 x 100 = 20%
Example