Compute the payback period for each of these two separate investments: a. A new operating system for an existing machine is expected to cost $300,000 and have a useful life of four years. The system yields an incremental after-tax income of $86,538 each year after deducting its straight-line depreciation. The predicted salvage value of the system is $12,000. b. A machine costs $200,000, has a $16,000 salvage value, is expected to last nine years, and will generate an after-tax income of $47,000 per year after straight-line depreciation. Payback Period Choose Numerator: Choose Denominator: Payback Period Payback period %3D a. b