Revision of we A building with a cost of $607,500 has an estimated residual value of $121,500, has an estimated useful life of 27 years, and is depreciated by the straight-line method. a. What is the amount of the annual depreciation? Do not round Intermediate calculations. b. What is the book value at the end of the fifteenth year of use? c. If at the start of the sixteenth year it is estimated that the remaining life is 15 years and that the residual value is $22,500, what is the depreciation expense for each of the remaining 15 years