A store sells prints and photographs. A photograph costs 20 to purchase and it takes 2 hours to frame each photo. A print costs 30 to purchase and it takes 5 hours to frame each print. The store has at most 500 to spend and at most 70 hours to frame. If the store makes 25 profit on each photo and 40 profit on each print, find the number of each that it should purchase to maximize profits