-28.57% is the change from 42 to 30
Calculation steps:
[( 30 - 42 ) ÷ 42] x 100 = -28.57%
Formula
Percentage change = [(30 - 42) / 42] x 100
Subtract the new number by the original number
30 - 42 = -12
-12 ÷ 42 = -0.2857142857142857
-0.2857142857142857 x 100 = -28.57%