Question: A factory uses raw materials x and y to produce products A and B. Each unit of product A requires 6 units of x and 3 of y; each unit of B, 5 of x and 6 of y. On hand there are 60 units of x and 55 units of y. The profits on the sales of A and B are 8.50 per unit and 9.75 per unit, respectively. How should the raw materials be used to realize a maximum profit? Fractional parts of units may be used.