Assume that you make the following investments:
a. You invest a lump sum of $8,000 for four years at 14% interest. What is the investment's value at the end of four years?
b. In a different account earning 14% interest, you invest $2,000 at the end of each year for four years. What is the investment's value at the end of four years?
c. What general rule of thumb explains the difference in the investments' future values?