Answer:
The sunk cost is the old broken machine
Explanation:
Giving the following information:
Model 370 machine costing $459,000
Model 240 machine costing $415,000
A machine was purchased 4 years ago for $423,000.
Management decided to buy the model 240.
A sunk cost is a cost that has previously been incurred and cannot be recovered. In this exercise, the sunk cost is the old broken machine. No matter what decision management makes, the machine is broken and can't be repaired or sold.