7. A machine purchased 9 years ago for $45,000 is expected to have the salvage values and operating costs as shown below. It can be disposed of now at a market value of S8,000. A replacement machine will cost $125,000 and will have a $10,000 salvage value after its 10-year life. Its annual operating cost is expected to be S31,000. At an interest rate of 15% per year, determine how many more years, if any, the company should retain the existing machine. operating Cost, SYear Year Salvage Value at End of Year, S 6,000 50,000 53,000 4,000 1,000 60,000