A company sells two different nut mixes. The cheapest mix contains 80% peanuts and 20% walnuts; while the most expensive one contains 50% of each type. Each week the company can obtain up to 1,800 kilos of peanuts and 1,200 kilos of walnuts from its supply sources. 

How many kilos of each mixture should they produce to maximize profits if profits are $10 for each kilo of the cheapest mix and $15 for each kilo of the most expensive mix?