A company sells two different mixes of nuts. The cheapest mix contains 80% peanuts and 20% walnuts; while the most expensive mix contains 50% of each. Each week, the company can source up to 1,800 pounds of peanuts and up to 1,200 pounds of walnuts from its supply sources. Profits are 10 for each pound of the cheaper mixture and 15 for each pound of the more expensive mixture. The company's goal is to maximize its profits.