Production Scheduling: National Business Machines manufactures tow models of portable printers: A and B. Each model A Cost $100 to make and each model B costs $150. The profits are $30 for each model A and $40 for each model B portable printer, If the total number if portable printers demanded per month does not exceed 2500 and the company has earmarked no more than $600,000/month for manufacturing costs, how many units of each model should National make each month to maximize its monthly profit?