Answer:
The old machine should be replaced.
Explanation:
Note: See the attached excel file for the the analysis showing whether the old machine should be retained or replaced.
From the attached excel file, the following calculation are made:
Variable Manufacturing cost of Retain = Initial Variable Manufacturing cost * remaining useful life of old machine = $592,600 * 5 = $2,963,000
Variable Manufacturing cost of Replace = New Variable Manufacturing cost * Remaining useful life of new machine = $505,500 * 5 = $2,527,500
From the attached excel, it can be observed that the total cost of Retain is $32,200 higher than the total cost of Replace. This therefore implies that the old machine should be replaced.