Answer:
Tim had nine cards with each having a distinct number from 1-9, meaning no number should be repeated twice while he tried to arrange them in piles while each pile should have a total of 15 when these numbers in the card are added all together.
I would arrange the ways below in rows and columns to make it easier to understand:
Ways Ist Pile 2nd Pile 3rd Pile
1st way: 5, 1, 9 2, 4, 6, 3 7, 8
2nd way: 1, 6, 8 5, 7, 3 4, 2, 9
3rd way: 9, 2, 3 , 1 4, 5, 6 8, 7
4th way: 4, 9, 2 7, 8 6, 3, 5, 1
5th way: 8, 2, 4, 1 9, 6 7, 5, 3
6th way: 1, 2. 3, 4, 5 7, 8 9, 6
7th way: 3, 8, 4 4, 6, 5 9, 1, 5
8th way: 1, 2, 5, 7 3, 4, 8 6, 9
9th way: 8, 5, 2 9, 6 1, 3, 4, 7