Munoz Rentals can purchase a van that costs $120,000; it has an expected useful life of four years and no salvage value. Munoz uses straight-line depreciation. Expected revenue is $50,580 per year. Assume that depreciation is the only expense associated with this investment Required a. Determine the payback period. (Round your answer to 1 decimal place.) b. Determine the unadjusted rate of return based on the average cost of the investment. (Round your answer to 1 decimal place. (i.e., 234 should be entered as 23.4).) : la. Payback period years b. Unadjusted rate of returrn