Purity Ice Cream Company bought a new ice cream maker at the beginning of the year at a cost of $24,000. The estimated useful life was four years, and the residual value was $2,580. Assume that the estimated productive life of the machine was 10,200 hours. Actual annual usage was 4,080 hours in year 1; 3,060 hours in year 2; 2,040 hours in year 3; and 1,020 hours in year 4.

Required:
1.	Complete a separate depreciation schedule for each of the alternative methods. (Do not round intermediate calculations.)

a. Straight-line Depreciation Accumulated Depreciation Net Book Value Year Expense At acquisition 2 4 b. Units-of-production (use four decimal places for the per unit output factor). Depreciation Accumulated Depreciation Net Book Value Year Expense At acquisition 2 4 c. Double-declining-balance Depreciation Accumulated Depreciation Net Book Value Year Expense At acquisition 4