Most of the required information's are already given in the question and based on those information's the answer to the question can be easily deduced.
Total number of penalties = 25
Percentage of decrease in penalty = 32%
Then
Amount of penalty decreased = (32/100) * 25
= 8
Then
The number of penalties after decrease = 25 - 8
= 17
So the number of penalties comes out to be equal to 17. I hope the procedur is clear enough for you to understand. You can definitely use this procedure for solving similar kind of problems in future without requiring any help from outside.