Before doing it please show why I came to the conclusion of two different answers

estimated to have no salvage value at the end of its 8-year useful life. If the equipment is purchased, annual revenues are expected to be $90,000 and annual operating expenses exclusive of depreciation expense are expected to be $40,000. The straight-line method of depreciation would be used. If the equipment is purchased, the annual rate of return expected on this equipment is a. 31.3%. b. 6.25%. c. 3.125%. d. 15.6%