I am having a hard time understanding this question. Could you please give me a solution?

Question 21 5 pts Porthos Corporation has invested in a machine that cost $60,000, that has a useful life of ten years, and that has no salvage value at the end of its useful life. The machine is being depreciated by the straight-line method, based on its useful life. It will have a payback period of four years. What is the accounting rate of return of this machine