A $20,000 investment in machinery is under consideration. The project is expected to have a life of 6 years and no salvage value. The estimated annual income from the project is $10,000 with annual operating expenses of $4,000. The investment will be depreciated by the MACRS (GDS) straight-line method based on a 5-year recovery period. If a 40% income tax rate is applied with a MARR of 5%, compute the present worth on the proposed investment's aftertax cash flow under the following financial policies:

a. The investment is provided from the firm's retained earnings. b. The initial investment is borrowed at 10% with repayment of interest at the end of each period and repayment of the loan principal at the end of 5 years. c. Repeat parts (a) and (b) for a MARR of 9%.