Revision of depreciation A building with a cost of 2 200 000 has an estimated residual value of 85 000 has an estimated useful life of 40 years and is depreciated by the straight line method a What is the amount of the annual depreciation b What is the book value at the end of the twenty eighth year of use c If at the start of the twenty ninth year it is estimated that the remaining life is 5 years and that the residual value is 60 000 what is the depreciation expense for each of the remaining 5 years