A three-year-old machine has a cost of $32,700, an estimated residual value of $1,200, and an estimated useful life of 35,000 machine hours. The company uses units-of-production depreciation and ran the machine 3,200 hours in year 1; 8,050 hours in year 2; and 7,400 hours in year 3. Calculate the net book value at the end of the third year. Net book value