E10-8 Relax-the-Back Mattress Store purchased a building for $775,000 and depreciated it on a straight-line basis over a 40-year period. The estimated residual value was $100.000. After using the building for 15 years, Relax-the-Back realized that wear and tear on the build- ing would force the company to replace it before 40 years. Starting with the 16th year, Relax- the-Back began depreciating the building over a revised total life of 30 years and increased the estimated residual value to $200,000. Record depreciation expense on the building for years 15 and 16.