The maintenance and operation (M&O) cost of a machine increases by a constant amount of $1500 per year for the first 5 years of operation. If this machine has a first cost of $30,000 and first-year M&O cost of $15,000, compare the equivalent annual worth of this machine kept for 3 years with one kept for 5 years at an interest rate of 10% per year. The salvage value of a used machine is $20,000 after 3 years and $15,000 after 5 years