-7.5% is the change from 40 to 37
Calculation steps:
[( 37 - 40 ) ÷ 40] x 100 = -7.5%
Formula
Percentage change = [(37 - 40) / 40] x 100
Subtract the new number by the original number
37 - 40 = -3
-3 ÷ 40 = -0.075
-0.075 x 100 = -7.5%
Example