Chapter 10 Long-Term Assets: Fixed and Intangible521 OBJ. 2 EE 10-2 Units-of-activity depreciation PE 10-2B A tractor acquired at a cost of $420,000 has an estimated residual value of $30,000, has an estimated useful life of 25,000 hours, and was operated 1,850 hours during the year Determine (a) the depreciable cost, (b) the depreciation rate, and (c) the units-of-activity depreciation for the year 497 Show Me How