Ford Motor Company purchased a building for $1,000,000. The building has a useful life of 25 years and a salvage value of $100,000. Calculate: a) The yearly depreciation expense using the sum-of-years-digits method. b) The accumulated depreciation at the end of year 10. c) The book value of the building at the end of year 15. d) The total depreciation expense over the building's useful life.