A machine purchased a year ago for $$85,000$ costs more to operate than

anticipated. At the time of the purchase, it was expected to be used for $10$

years with annual maintenance costs of $$22,000$ and a salvage value of

$$10,000.$ However, last year, it incurred a cost $$31,000,$ which is expected to

escalate to $$32,400$ this year and increase by $$1,400$ each year thereafter. The

market value is now estimated to be $$78,000-$$$10,000k,$ where $k$ is the

number of years since the machine was purchased. It is now estimated that the

machine will be useful for a maximum of $4$ more years. A replacement study is

to be performed. Determine the values of $P,n,$AOC for year $4$ and $S$ of this

defender.

The value of $P$ is $

The value of $n$ is

years.

The AOC for year $4$ is

The value of $S$ is $