11. A manufacturer produces two products, and B, which are sold in two markets. The weekly demand functions, in dollars, are: p = 600 -0.4x and py = 400 -0.2y, where x and y are units of each product. The weekly cost function is: C(x,y) = 60,000+ 30x + 40y a. Determine the total weekly revenue function R(x,y). b. Determine the total weekly profit function P(x,y). c. Determine how many units of each product should be produced and sold weekly to maximize the manufacturers' total weekly profit