The percent decrease we are going to use is "x"
If something decreases by 30%, then you are actually multiplying the number by 70%, which is 100% - 30% = 70%.
Therefore:
60 (1 - x) = 39
60 - 60x = 39
-60x = -21
x = 0.35 or 35%
The percent decreased 35% from 60 to 39
