A punch press takes in coils of sheet metal and can make five different electrical breaker boxes, denoted by B1, B2, B3, B4, and B5. Each box takes exactly one minute to produce. To switch the process from one type of box to another takes four hours. There is demand of 1,800, 1,000,600,350, and 200 units per month for boxes Bl, B2, B3, B4, and B5, respectively. The plant works one shift, five days per week. After lunch, breaks, etc., there is seven hours available per shift. Assume 52 weeks per year. (a) What is ra in boxes