The sales S (in thousands of units) of a new product after it has been on the market t years is

$\displaystyle S=Ce^{k/t}$

a. Find s as a function of t if 5,000 units have been sold after 1 year and the saturation point for the market is 30,000 (that is, lim (as t approaches infinity) S=30).

b. How many units will have been sold after 5 years?

c. Use a graphing utility to graph this sales function.