I know how to do mixed fractions, just stuck on this one...9 2/5+8 2/3+7 11/15 help please I keep getting 25 2/15 what am I doing wrong

The common denominator is 15, and the sum can be written

9 6/15 +
8 10/15 +
7 11/15 =
---------
24 27/15 =
25 12/15 = 25 4/5

You are doing something wrong.