54. On January 1, 2018, Conway Company purchased a delivery vehicle costing $20,000. The vehicle has an estimated 5-year life and a $2,000 residual value. Conway estimates that the vehicle will be driven 100,000 miles. What is the vehicle's book value as of December 31, 2019 assuming Conway uses the units-of-production depreciation method and the vehicle was driven 10,000 miles during 2018 and 18,000 miles during 2019