Struggling on understand how to go about this question. Thanks for the assistance

A store sells two brands of camping chairs. The store pays $40 for each brand A chair and $50 for each brand B chair. The research department has estimated that the weekly demand equations for these two competitive products to be the following, where p is the selling price for brand A, q is the selling price for brand B, and x and y are the average number of chairs sold per week. Complete parts (A) and (B) below. x = 321 -3p + q Demand equation for brand A y = 779+ p-5q Demand equation for brand B (A) Determine the demands for x and y when p = $60 and q = $100. The demand for x will be (Type a whole number.) The demand for y will be (Type a whole number.) Determine the demands for x and y when p = $80 and q = $50. The demand for x will be (Type a whole number.) The demand for y will be (Type a whole number.) (B) How should the store price each chair to maximize weekly profits? What is the maximum weekly profit? [Hint: C = 40x + 50y, R = px + qy, and P = R - C.] The equation for P is P(p,q) = To maximize profit, the brand A chair should be priced at $ and the brand B chair should be priced at $ (Type integers or decimals rounded to two decimal places as needed.)