Gates co purchased machinery on January 2 , 2007 for 660000. The straight line method is used and useful life is estimated to be 10 years with a 60000 salvage value . at the beginning of 2013 gates spent 144000 to overhaul the machinery. After the overhaul gates estimated that the useful life would be extended 4 years. And the salvage value would be 30000. The depreciation expense for 2013 should be?