Revision of Depreciation Equipment with a cost of $240,000 has an estimated residual value of $18,600, has an estimated useful life of 12 years, and is depreciated by the straight line method: an Determine the amount of the annual depreciation. b. Determine the book value at the end of the tenth year of use. C. Assuming that at the start of the eleventh year the remaining life is estimated to be four years and the residual value is estimated to be $4,800, determine the depreciation expense for each of the remaining four years