Answer:
The incremental income over five-year useful life of the new machine is $(78,000).
Step-by-step explanation:
Incremental income over five-year useful life of the new machine is equal to the total of each profit&loss item below:
+ Loss on the sell of old machine = Selling price of the old machine - Book value of the old machine = 73,000 - 121,000 = $(48,000)
+ Depreciation expenses of new machine during 5 years = Cost of of the machine = $(120,000)
+ Variable cost savings during five year = 18,000 x 5 = $90,000.
=> Incremental income of replacing the old machine by the new one = (48,000) + (120,000) + 90,000 = $(78,000).
So, the result is $(78,000).