Exercise A$-18($Static$)$ Investment Decision with Unknown Economic Life

Mitchell Company is considering an investment in a new machine. Managers at the company are uncertain about the economic life of the machine, because of the speed of innovation in the technology. The machine requires an investment of $$1\mathrm{.}56$ million. After$-$tax cash flows are estimated to be $$650,000$ each year the machine is operating $($and not obsolete$).$ The company uses a $14$ percent discount rate in evaluating capital investments. Use Exhibit A$\mathrm{.}9.$

Required:

What is the minimum economic life of the machine $($in whole years$)$ that would be required for it to have a positive net present value?