rocko incorporated has a machine with a book value of $50,000 and a five-year remaining life. a new machine is available at a cost of $85,000 and rocko can also receive $38,000 for trading in the old machine. the old machine has variable manufacturing costs of $24,000 per year. the new machine will reduce variable manufacturing costs by $14,000 per year over its five-year life. should the machine be replaced?