Acompany manufactures mechanical heart valves from the heart valves of pigs. different heart operations require valves of different sizes. the company purchases pig valves from three different suppliers. the cost and size mix of the valves purchased from each supplier are given in the file p03_36.xlsx. this file also contains the maximum number of valves available from each supplier per month. each month, the company places an order with each supplier. at least 1300 large, 900 medium, and 400 small valves must be purchased each month. use solver to determine how the company can minimize the cost of acquiring the needed valves.