Average rate of return, cash payback period, net present value method for a service company minimum desired rate of return for net present value analysis is $\backslash (12\backslash \%\backslash ).$ Compute the following: a$.$ The average rate of return, giving effect to straight$-$line depreciation on the investment. If required, round your answer to one decimal place. $\backslash [\backslash \%\backslash ]$ b$.$ The cash payback period.