A local manufacturing firm produces four different metal products, each of which must be machined, polished and assembled. The specific time requirements (in hours) for each product are as follows: Machining, hours Polishing, hours Assembling, hours Product I 3 1 2 Product II 2 1 1 Product III 2 2 2 Product IV 4 3 1 The firm has available to it on weekly basis, 480 hours of machining time, 400 hours of polishing time and 400 hours of assembling time. The unit profits on the product