Calculate 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 residual value of the system is $10,000 2. A machine costs $190,000 and has a $10,000 residual value, is expected to last nine years, and will generate an after tax income of $30,000 per year after straight line depreciation