Mammoth Company purchased packaging equipment on January 3, 2008, for $67,500. The equipment was expected to have a useful life of three years, or 25,000 operating hours, and a residual value of $4,500. The equipment was used for 12,000 hours during 2008, 9,000 hours in 2009, and 4,000 hours in 2010.
Determine the amount of depreciation expense for the years ended December 31, 2008, 2009, and 2010, by (a) the straight-line method, (b) the units-of-production method, and (c) the double-declining-balance method. Also determine the total depreciation expense for the three years by each method.