The cost of a machine for producing a certain part is $60,000. The machine is expected to have an annual maintenance cost of $10,000 and an $4,000 salvage value after its 5-year economic life. If the variable cost for producing the part is $2.00 per unit and the part can be sold for $4.00 per unit, how many parts per year must the company sell in order to breakeven at an interest rate of 10% per year?