On July 1, 2013, Morrow Inc. purchased a spooler at a cost of $40,000. The equipment is expected to last eight years and have a residual value of $4,000. Instructions: Compute depreciation for 2013, 2014 and 2015 and the book value of the drill press at December 31, 2015, assuming the (a) sum-of-the-years'-digits method is used. (b) double declining balance