-15% is the change from 60 to 51
Calculation steps:
[( 51 - 60 ) ÷ 60] x 100 = -15%
Formula
Percentage change = [(51 - 60) / 60] x 100
Subtract the new number by the original number
51 - 60 = -9
-9 ÷ 60 = -0.15
-0.15 x 100 = -15%
Example