Please, solve mathematical model. Excel is not neccessary.

Problem 1. (20 pts) IP modeling State University must purchase 1100 computers from three vendors. Vendor 1 charges $500 per computer plus a total delivery charge of $5000. Vendor 2 charges $350 per computer plus total delivery charge of $4000. Vendor 3 charges $250 per computer plus a total delivery charge of $6000. Vendor 1 will sell the university at most 500 computers, vendor 2, at most 900, and vendor 3, at most 400. The minimum order from a vendor is 200 computers. Determine how to minimize the cost of purchasing the needed computers. (You need to define your decision variables clearly to receive full credit.)