7.28 Consider two investments with the following sequences of cash flows: 0 Net Cash Flow Project A Project B -$30,000 -$15,000 $2,000 $10,000 $6,000 $10,000 $12,000 $10,000 $24,000 $10,000 $28.000 $5,000 (a) Compute the i for cach investment. (b) Plot the present worth curve for each project on the same chart and find the interest rate that makes the two projects equivalent. (c) If A and B are mutually exclusive investment projects, which project is more economically desirable at MARR of 15%