Marshall Technology is considering two alternative proposals for modernizing its production facilities. To provide a basis for selection the cost accounting department has developed the following data regarding the expected annual operating results for the two proposals. Items in addition to depreciation may have attributed to differences in the estimated annual cash flow and net income figures shown below. required investment in equipment proposal a 480,000 proposal b 448,000 estimated service life of equipment proposal a 8 years proposal b 7 years estimated salvage value proposal a 0 proposal b 56,000 estimated annual net cash flow proposal a 80,000 proposal b 112,000 estimated increase in annual net income proposal a 48,000 proposal b 37,800 for each proposal compute pay back period return on average investment net present value discounted at an annual rate of 12 percent ( round the return on investment to the nearest tenth of a percent) use where necessary b on the basis of your analysis in part a state which proposal you would recommend and explain the reasons for your choice