1 3 4 5 Year CF 0 -28000 2 11,000 3 10,000 9,500 9,500 11,500 10,600 Rate 11% The initial investment is $28000. The firm has a required rate of return of 11 per cent. Calculate: a. The payback period: (PP) b. The discounted payback period: (DPP) C. The net present value; (NPV) d. The internal rate of return; (IRR)