A potato chip company makes chips to fill snack-size bags and family size bag. in one week production cannot exceed 2400 units, of which at least 600 units must be for snake size bags and at least 900 units it must be for family size. The profit on a unit of snack size bags is 12$, and the profit on a unit of family size bags is $18. How much of each type of bag must be processed to maximize profits?