Ford Motor Company purchased a building for $1,500,000. The building has a useful life of 30 years and a salvage value of $150,000. Calculate: a) The yearly depreciation expense using the sum-of-years-digits method. b) The accumulated depreciation at the end of year 15. c) The book value of the building at the end of year 20. d) The total depreciation expense over the building's useful life. e) Assess the impact of depreciation on the company's fixed assets.