An automobile company is ready to introduce a new line of cars through a national sales campaign. After test marketing the line in a carefully selected city, the marketing research department estimates that the sales (in millions of dollars) will increase at the monthly rate of the following function for t months after the campaign has started.

S'(t)=15-20e[Power-0.1t] 0<_t<_22

A. What will be the total sales, S(t), t months after the beginning of the national sales campaign if we assume no sales at the beginning of the campaign?

B. What are the estimated total sales for the first 9 months of the campaign?

C. When will the estimated total sales reach $120 million? Use a graphing calculator to approximate the solution to the equation

S(t)=120.