Let x be the price per pound of apples and y be the price per pound of potatoes.
For Ethan, the total cost for apples was $25.50 - 5y and the total cost for potatoes was $25.50 - 8x.
So, we have the following two equations:
8x + 5y = 25.5
3x + 10y = 18.5
Solving this system of linear equations, we get:
x = 1.71 and y = 2.36.
So, the ordered pair (x,y) = (1.71, 2.36) represents the price per pound of apples and potatoes.