Colquhoun International purchases a warehouse for $311,000. The best estimate of the salvage value at the time of purchase was $16,000, and it is expected to be used for twenty-five years. Colquhoun uses the straight-line depreciation method for all warehouse buildings. After four years of recording depreciation, Colquhoun determines that the warehouse will be useful for only another fifteen years.

Required:
a. Calculate annual depreciation expense for the first four years.
b. Determine the depreciation expense for the final fifteen years of the asset’s life.