-29.17% is the change from 240 to 170
Calculation steps:
[( 170 - 240 ) ÷ 240] x 100 = -29.17%
Formula
Percentage change = [(170 - 240) / 240] x 100
Subtract the new number by the original number
170 - 240 = -70
-70 ÷ 240 = -0.2916666666666667
-0.2916666666666667 x 100 = -29.17%