Based on Kalvaitishi and Posgay (1974). A direct mail company must determine which of 10 mailing lists to use this month to generate a catalog mailing. The number of names in each list, the mainframe computer time (in hours) needed to process the list, the labor time per letter mailed for each list (in minutes), the number of names (in hundreds of thousands) on each list, the response rate from each list, and the average profit per order from each list are given in the file P06_89.xlsx. It costs $100,000 per month to rent a mainframe computer. A rented computer can be used for up to 100 hours in any given month. The company has 400 employees who each work 160 hours per month. Develop a linear integer model to help the company maximize its monthly profit.