-32.5% is the change from 40 to 27
Calculation steps:
[( 27 - 40 ) ÷ 40] x 100 = -32.5%
Formula
Percentage change = [(27 - 40) / 40] x 100
Subtract the new number by the original number
27 - 40 = -13
-13 ÷ 40 = -0.325
-0.325 x 100 = -32.5%
Example