The monthly revenue R achieved by selling x wristwatches is figured to be R(x)=71x-0.2x. The monthly cost C of selling x wristwatches is C(x) = 30x + 1750 (a) How many wristwatches must the firm sell to maximize revenue? What is the maximum revenue? (b) Profit is given as P(x) = R(x)-C(x). What is the profit function? (c) How many wristwatches must the firm sell to maximize profit? What is the maximum profit? (d) Provide a reasonable explanation as to why the answers found in parts (a) and (c) differ. Explain why a quadratic function is a reasonable model for revenus (a) The firm must sell wristwatches to maximize revenue. (Round to the nearest integer as needed.) The maximum revenue is $ (Round to two decimal places as needed.)