doranti inc is considering two mutually exclusive projects. dorant used a 15% required rate of teturn to evaluate capital expenditure projects. if two projects have the costs and cash flows shown below determine the npv, pi, irr, payback and discounted payback for each project. year 0, 1, 2, 3, 4- project s -$70,000, 50,000, 60,000 and project t -$100,000, 60,000, 70,000, 80,000, 90,000