The Cardinal Gym needs to purchase an exercise machine to attract more customers. There are two feasible machines in the market: machine A and machine B. Purchase of machine A needs an initial cost of $40,000, annual maintenance cost of $20,000 and a salvage value of $10,000 at the end of 4 years. Purchase of machine B needs an initial cost of $75,000, annual maintenance cost of $15,000 and a salvage value of $7,000 at the end of 6 years. Please use annual worth comparison to determine which machine should be purchased in Cardinal Gym at an interest rate of 12%