E11-4 (Depreciation ComputationsFive Methods) Wenner Furnace Corp. purchased machinery for $279,000 on May 1, 2010. It is estimated that it will have a useful life of 10 years, salvage value of $15,000, production of 240,000 units, and working hours of 25,000. During 2011 Wenner Corp. uses the machinery for 2,650 hours, and the machinery produces 25,500 units