Perdue Company purchased equipment on April 1, 2012, for $270,000. The equipment was expected to have a useful life of three years, or 18,000 operating hours, and a residual value of $9,000. The equipment was used for 7,500 hours during 2012, 5,500 hours in 2013, 4,000 hours in 2014, and 1,000 hours in 2015.

Required:

Determine the amount of depreciation expense for the years ended December 31, 2012, 2013, 2014, and 2015, by (a) the straight-line method, (b) units-of-output method, and (c) the double-declining-balance method.