Depreciation by three methods: partial years Layton Company purchased tool sharpening equipment on October 1 for $108,000. The equipment was expected to have a useful life of three years or 12,000 operating hours, and a residual value of $7,200. The equipment was used for 1,350 hours during Year 1, 4,200 hours in Year 2, 3,650 hours in Year 3, and 2,800 hours in Year 4. Determine the amount of depreciation expense for the years ended December 31, Year 1, Year 2, Year 3, and Year 4, by (A) the straight-line method, (B) the units-of-activity method, and (C) the double-declining-balance method