Suppose that in a monopoly market, the demand function for a product is given by p = 160 - 0.1x where x is the number of units and p is the price in dollars.
(a) Find the total revenue from the sale of 500 units.
(b) Find and interpret the marginal revenue at 500 units.
(c) Is more revenue expected from the 501st unit sold or from the 701st? Explain.