18. Calculate the NPV for the following projects. a. An outflow of $7,000 followed by inflows of $3,000, $2,500 and $3,500 at one-year intervals at a cost of capital of 7% b. An initial outlay of $35.400 followed by inflows of $6,500 for three years and then a single inflow in the fourth year of $18,000 at a cost of capital of 9%. (Recognize the first three inflows as an annuity in your calculations.) c. An initial outlay of $27,500 followed by an inflow of $3,000 followed by five years of inflows of $5,500 at a cost of capital of 10% (Recognize the last five inflows as an annuity, but notice that it requires a treatment different from the annuity in part b. (10 POINTS)