A company is considering purchasing factory equipment that costs $320,000 and is estimated to have a $20,000 salvage value at the end of its 6-year useful life. If the equipment is purchased, annual revenues are expected to be $90,000 and annual operating expenses including depreciation expense are expected to be $78,000. The straight-line method of depreciation would be used. If the equipment is purchased, the annual rate of return (rounded) on this equipment is 7.5% 6.7% 7.1% 3.5%