-78% is the change from 50 to 11
Calculation steps:
[( 11 - 50 ) ÷ 50] x 100 = -78%
Formula
Percentage change = [(11 - 50) / 50] x 100
Subtract the new number by the original number
11 - 50 = -39
-39 ÷ 50 = -0.78
-0.78 x 100 = -78%
Example