On January 1, Year 1, Dunn Brothers, Inc., purchased a new smartphone case making machine at a cost of $44,000. The estimated residual value was $5,000. Assume that the estimated useful life was four years and the estimated productive life of the machine was 390,000 units. Actual annual production was as follows: Year Units 1 117,000 2 85,800 3 107,250 4 79,950 Required:

a. Calculate depreciation expense under the Straight-line method for Years 1 to 4.

b. Calculate depreciation expense under the Units-of-production method for Years 1 to 4.

c. Complete a depreciation schedule under the Double-declining-balance method.