Compute the payback period for each of these two separate investments ( round the payback period to two decimals) : a. a new operating system for an existing machine is expected to cost $520,000 and have a useful life of six years, the system yields an incremental after-tax income of $150,000 each year after deducting its straight-line depreciation. the predicted salvage value of the system is $10,000.b. a machine cost $380,000, has a $20,000 salvage value, is expected to last eight years, and will generate an after-tax income of $60,000 per year after straight-line depreciation.