Bob Sledding Company, a wholesale distributor of children's sleds, is considering the purchase of a $45,000 machine that would reduce operating costs in its warehouse by $7,000 per year. At the end of the machine's 9-year useful life, it will have no scrap value. The company's required rate of return is 14%. a) What is the payback period? b). Determine the NPV of the investment in the machine. c) Determine the NPV if Bob reduces its required return to 7%