A department store wishes to purchase 7,500 purses of which 2,500 are of style X, 2,500 are of style Y and 2,500 are of style Z. Four manufacturers A, B, C and D bid to supply not more than the following quantities, all styles combined. A = 1,000, B = 3,000, C = 2,100 and D = 1,900. The following table gives the cost per purse of each style of the bidders in dollars per purse. X Y Z 10 AB 10 6 7 4 7 8 C 6 8 7 D 5 8 9 Develop a linear programming model for the above given problem. (Do not solve it)