A piece of equipment has a first cost of $165.000, a maximum useful life of 7 years, and a market (salvage) value described by the relation S -120.000 25.000k, where k is the number of years since it was purchased. The salvage value cannot go below zero. The AOC series is estimated using AOC = 60.000 + 13.000k. The interest rate is 11% per year. Determine the economic service life and the respective AW The economic service life is year(s) and the AW value is $ [ ]