It is estimated that t weeks from now, contributions in response to a fundraising campaign will be coming in at the rate of R'(t) = 5,000e^−0.2t dollars per week, while campaign expenses are expected to accumulate at the constant rate of $676 per week.

a. For how many weeks does the rate of revenue exceed the rate of cost?

b. What net earnings will be generated by the campaign during the period of time determined in part (a)?

c. Interpret the net earnings in part (b) as an area between two curves.