Units-of-activity depreciation A truck acquired at a cost of $60,000 has an estimated residual value of $2,000, has an estimated useful life of 200,000 miles, and was driven 15,000 miles during the year. Determine the following. If required, round your answer for the depreciation rate to 2 decimal places. (a) The depreciable cost (b) The depreciation rate S per mile (c) The units-of-activity depreciation for the year