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The cost of equipment purchased by Charleston, Inc., on June 1, 2020, is $89,000. It is estimated that the machine will have a $5,000 salvage value at the end of its service life. Its service life is estimated at 7 years, its total working hours are estimated at 42,000, and its total production is estimated at 525,000 units. During 2020, the machine was operated 6,000 hours and produced 55,000 units. During 2021, the machine was operated 5,500 hours and produced 48,000 units. Compute depreciation expense on the machine for the year ending December 31, 2020, and the year ending December 31, 2021, using the following methods. (Round depreciation per unit to 2 decimal places, e.g. 15.25 and final answers to 0 decimal places, e.g. 45,892.) 2020 2021 (a) Straight-line 7000 12000 (b) Units-of-output 8800 7680 (c) Working hours 12000 11000 (d) Sum-of-the-years'-digits 12250 19250 (e) Double-declining-balance (twice the straight-line rate) 14833 21190