Compute the payback period for each of these two separate investments:

1. A new operating system for an existing machine is expected to cost $260,000 and have a useful life of five years. The system yields an incremental after-tax income of $75,000 each year after deducting its straight-line depreciation. The predicted salvage value of the system is $10,000.
2. A machine costs $180,000, has a $14,000 salvage value, is expected to last nine years, and will generate an after-tax income of $41,000 per year after straight-line depreciation

   Payback Period
   	Choose Numerator:	/	Choose Denominator:	=	Payback Period
   		/		=	Payback period
   a.				=
   b.				=