Answer:
The seniors made 8 pies.
Explanation:
Each pie has 5 pieces to sell, and there was a total of 60 pieces. The teacher contributed 4 pies, or 20 slices. The seniors would have had to have 40 slices for a total of 60 slices. 8 pies with 5 pieces each makes 40. Therefore, the seniors made 8 pies.