a presently owned machine can last 3 more years if properly maintained at a cost of $14,000 per year. its aoc is $30,000 per year. after 3 years, it can be sold for an estimated $9,000. a replacement costs $85,000 with a $10,000 salvage value after 3 years and an operating cost of $22,000 per year. different vendors have offered $10,000 and $22,000, respectively, for the current system as a trade-in for the replacement machine. at i