Linear Programming: The polar sports company both manufactures snowboards and skis. it takes 8 hours to manufacture a snowboard and 10 hours to manufacture a set of skis, there are 400 hours of labor available each week for production. Due to demand, they must produce at least 15 snowboards. Snowboards profit $55 each and skis profit $80 each. How many should they produce in a week to maximize their profit?