A company produces two models of a surfboard: a standard model and a competition model. If the standard model is produced at a variable cost of $220 each and the competition model at a variable cost of $320 each, and if the total fixed costs per month are $6,000, then the monthly cost function is given by C(x,y) = 6,000+220x + 320y where x and y are the numbers of standard and competition models produced per month, respectively. Find C(24,12), C(40,4), and C(40,40). C(24 12)=$ (Simplify your answer.)