Answer:a. The company will be $11,000 better off over the 5 year period if it replaces the old machine.
Step-by-step explanation:
The purchase of the new machine will bring the annual operating expenses to $9,000 compared to the $15,000 been spent on the old machine which brings in a savings of $6000 and when this is added to the $ 5000 increase sales revenue from the new machine, it means the company will be better off by $11,000 over the next five year if it replaces the old machine.
There is no justification for being $12,000, $20,000 or $6000 better off over the next five year by either replacing or keeping the old machine.