please explain how you got the answer for annual rate of return please and ill thumbs up

Legend Service Center just purchased an automobile hoist for $36,900. The hoist has an 8 -year life and an estimated salvage value of $3,000. Installation costs and freight charges were $3,900 and $800, respectively. Legend uses straight-line depreciation. The new hoist will be used to replace mufflers and tires on automobiles. Legend estimates that the new hoist will enable his mechanics to replace 5 extra mufflers per week. Each muffler sells for $71 installed. The cost of a muffler is $39, and the labor cost to install a mutfier is $12. (a) Compute the cash payback period for the new hoist. Cash payback period years (b) Compute the annual rate of return for the new hoist. (Round answer to 2 decimal places, eg. 10.52\%) Annual rate of return %