A company manufactures 10 - and 3 - speed bicycles. The weekly demand and cost equations are
p = 230 - 9x + y
q = 130 + x - 4y
C(x,y) = 200 + 80x + 30y
where %p is the price of a 10 - speed bicycle, $q is the price of a 3 - speed bicycle, x is the weekly demand for 10-speed bicycles, y is the weekly demand for 3 - speed bicycles, and C(x, y) is the cost function. Find the weekly revenue function R(x, y) and the weekly profit function P(x, y). Evaluate R(10,15) and P(l0, 15).