Determine how many deluxe copies and how many standard

Question

Question: MAXIMIZING PROFIT The total daily revenue (in dollars) that Weston Publishing realizes in publishing and selling its English-language dictionaries is given by

R(x, y) = -0.005x² - 0.003y² - 0.002xy + 20x + 15y

Where x denotes the number of deluxe copies and y denotes the number of standard copies published and sold daily. The total daily cost of publishing these dictionaries is given by

C(x, y) = 6x + 3y + 200

Dollars. Determine how many deluxe copies and how many standard copies Weston should publish each day to maximize its profits. What is the maximum profit realizable?