Answer:
Total costs are reduced with the new machine.
Step-by-step explanation:
scenario 1: keep using old machine
machine cost = $88,100
variable expenses = $576,600 x 7 = $4,036,200
total expenses for 7 years = $4,124,300
scenario 2: purchase new machine
machine cost = $510,700 - $33,800 = $476,900
variable expenses = $470,500 x 7 = $3,293,500
total expenses for 7 years = $3,770,400
difference in total expenses = $3,770,400 - $4,124,300 = $353,900 favorable for new machine
Since the total costs are lower when you purchase the new machine, then you should go ahead and do it. Generally when you carry on a project that needs a significant investment like this new machine, you should use an interest rate to calculate present value, but you could also lease the machine instead of purchasing it (since it has no residual value).