An entrepreneurial civil engineer who owns his own design/build company purchased a small crane 2 years ago at a cost of $71,000. At that time, it was expected to be used for 10 years and then traded in for its salvage value of $10,000.

Due to increased construction activities, the company would prefer to trade for a new, larger crane now which will cost $93,000. The company estimates that the old crane can be used, if necessary, for another 4 years, at which time it will have a $25,000 estimated market value. Its current market value is estimated to be $39,000, and if it is used for another 4 years, it will have M&O costs of $17,000 per year. Determine the values of P, n, S, and AOC that should be used for the existing crane in a replacement analysis performed today.