Exercise (17] The cost of Truck $ ? , Salvage vaiue $ 10,000, and the useful life 4year, its purchased at Jan,1,2019, using units of activity if estimated units 20,000 units Required; Calculate the Annual depreciation and the Book Value at the year ended Dec,2020 if the actual miles were 15000 miles, and the depreciation expense at Dec,31,2019 was $10,000 and actual miles for 2019 was 20,000 miles