18. Consider the demand for cupcakes in Problem 17. Suppose Elaine decides to sell cupcakes only in packages of 20.

a. How much would customers be willing to pay to obtain a 20-pack of Elaine’s cupcakes?
(Hint: Remember that the value of each cupcake is given by the corresponding point on the demand curve. Add up those values for cupcakes 1–20.)

b. How much profit will Elaine earn from each customer?

c. How does the profit from this scheme compare to the profit Elaine earned in part

(f) of Problem 17?