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Compute the payback period for each of these two separate investments: a. A new operating system for an existing machine is expected to cost $250,000 and have a useful life of four years. The system yields an incremental after-tax income of $72,115 each year after deducting its straight-line depreciation. The predicted salvage value of the system is $10,000. b. A machine costs $170,000, has a $13,000 salvage value, is expected to last nine years, and will generate an after-tax income of $39,000 per year after straight-line depreciation. Payback Period Choose Numerator: Choose Denominator: Payback Period Cost of investment Annual net cash flow E Payback period a. $ 250,000 $ 120,115 2.08 years b $ 170,000 0