On January 1, 2019, Wasson Company purchased a delivery vehicle costing $47,550. The vehicle has an estimated 7-year life and a $4,500 residual value. Wasson uses the units-of-production depreciation method and Wasson estimates that the vehicle will be driven 105,000 miles. What is the vehicle's book value as of December 31, 2020, assuming the vehicle was driven 10,500 miles during 2019 and driven 18,500 miles during 2020