Lilly buys fresh fruit from a fruit stand. Apples cost $5 per pound and oranges cost $4 per pound. She has $40 to spend. The table shows the function relating the number of pounds of apples, x, and the number of pounds of oranges, y, Lilly could purchase.

Apples (lb) Peaches (lb)
x y
0 10
1 8.75
2 7.5
4 5
6 2.5
8 0