Redwood Corporation is considering two alternative investment proposals with the following data: Proposal X Proposal Y Investment $860,000 $505,000 Useful life 8 years 8 years Estimated annual net cash inflows for 8 years $130,000 $89,000 Residual value $52,000 $- Depreciation method Straight-line Straight-line Required rate of return 16% 14% How long is the payback period for Proposal X