Formulate but do not solve the following exercise as a linear programming problem. National Business Machines manufactures x model A fax machines and y model B fax machines. Each model A cost $100 to make, and each model B costs $150. The profits are $30 for each model A and $45 for each model B fax machine. If the total number of fax machines demanded per month does not exceed 1800 and the company has earmarked not more than $600,000/month for manufacturing costs, how many units of each model should National make each month to maximize its monthly profits P in dollars?

Maximize		P	=		subject to the constraints
manufacturing costs
number produced
				x 0
				y 0