The management of Stanforth Corporation is investigating automating a process. Old equipment, with a current salvage value of $24,000, would be replaced by a new machine. The new machine would be purchased for $516,000 and would have a 6 year useful life and no salvage value. By automating the process, the company would save $173,000 per year in cash operating costs. What would be the simple rate of return on the investment?