Steel is purchased on July 1 of the current fiscal year for $180,000. It is expected to have a useful life of 4 years, or 20,000 operating hours, and a residual value of $15,000. Compute the depreciation for the last six months of the current fiscal year ending December 31 by each of the following methods:
-straight line method
-declinding balance at twice the straigh line rate
-units of production (used for 1,500 hours during the current year)