150% is the change from 20 to 50
Calculation steps:
[( 50 - 20 ) ÷ 20] x 100 = 150%
Formula
Percentage change = [(50 - 20) / 20] x 100
Subtract the new number by the original number
50 - 20 = 30
30 ÷ 20 = 1.5
1.5 x 100 = 150%
Example