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. a. Determine the amount of the annual depreciation. s 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 4 years and the residual value is estimated to be $4,800, determine the depreciation expense for each of the remaining 4 years