Before starting to solve the problems, it is important to look at all the information's that are given in the question. Based on those information's the answer can be deduced very easily.
Number of downloaded songs that Herman has in his collection = 240
Number of downloaded songs that Herman has after deleting some songs = 180
Then
Percentage of original collection of Herman = (180/240) * 100
= (3/4) * 100
= 3 * 25
= 75 percent
So Herman has kept 75 of his original collection. I hope the procedure is clear enough for you to attempt such problems in future without requiring any outside help.
