Magenta 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		$81,600		Cost		$39,000
Accumulated depreciation		$41,600		Estimated useful life		8 years
Remaining life		8 years		Salvage value in 8 years		$4,600
Current salvage value		$10,920		Annual cash operating costs		$30,000
Salvage value in 8 years		$0
Annual cash operating costs		$35,200

Depreciation is $10,200 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.

Determine the cash payback period in years. (Ignore income taxes.) (Round answer to 3 decimal places, e.g. 15.275.)