Shamrock Inc. is considering modernizing its production facility by investing in new equipment and selling the old equipment. The following information has been collected on this investment: Old Equipment New Equipment Cost $80,640 Cost $39,000 Accumulated depreciation Remaining life Current salvage value Salvage value in 8 years 8 years Salvage value in 8 years $40,600 Estimated useful life 8 years $4,600 $10,400 Annual cash operating costs $29,900 $0 Annual cash operating costs $35,100 Depreciation is $10,080 per year for the old equipment. The straight-line depreciation method would be used for the new equipment over an eight-year period with salvage value of $4,600. (a) Determine the cash payback period. (Ignore income taxes.) (Round answer to 3 decimal places, e.g. 15.275) Cash payback period years