The marketing research department for a company that manufactures and sells memory chips for microcomputers established the following price–demand and revenue functions:

p(x) = 75 - 3x                      Price–demand function 

R(x) = xp(x) = x(75 - 3x)                 Revenue function

where p(x) is the wholesale price in dollars at which x million chips can be sold, and R(x) is in millions of dollars. Both functions have domain 1 ≤ x ≤ 20.

(A) Sketch a graph of the revenue function in a rectangular coordinate system.
(B) Find the value of x that will produce the maximum revenue. What is the maximum revenue?
(C) What is the wholesale price per chip that produces the maximum revenue?