Average rate of return, cash payback period, net present value method for a service company

The St$.$ Louis to Seattle Railroad is considering acquiring equipment at a cost of $$320,000.$ The equipment has an estimated life of $10$ years and no residual value. It is expected to provide yearly net cash flows of $$40,000.$ The company's minimum desired rate of return for net present value analysis is $12\%.$

$\backslash$table$[[$Present Value of an Annuity of $$1$ at Compound Interest$],[$Year$,6\%,10\%,12\%,15\%,20\%$