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. a. Straight-line method Year Amount