11. 9.41 A machine was purchased 3 years ago for $45,000; it can be sold today for $24,000. The operating costs for this machine are $9000 per year, and it is expected to last 4 more years with a $5000 salvage value. Used machines similar to this one will be available at any time in the future. A new machine that will perform the same service can be purchased for $50,000, and it will have a life of 10 years with operating costs of $28,000 per year and a $10,000 salvage value. The years that should be used for the life, n, in calculating the AW of the presently owned machine are: 1. 3 2. 4 3. 7 4. 10