Waterway Corporation purchased a new machine for its assembly process on August 1, 2020. The cost of this machine was $162,900. The company estimated that the machine would have a salvage value of $18,900 at the end of its service life. Its life is estimated at 5 years, and its working hours are estimated at 20,000 hours. Year-end is December 31.
Compute the depreciation expense under the following methods. Each of the following should be considered unrelated. (Round depreciation rate per hour to 2 decimal places, e.g. 5.35 for computational purposes. Round your answers to O decimal places, e.g. 45,892.)
(a) Straight-line depreciation for 2020
(b) Activity method for 2020, assuming that machine usage was 780 hours
(c) Sum-of-the-years'-digits for 2021
(d) Double-declining-balance for 2021

Activity method depreciation considers depreciation over the estimated usage of the asset and multiplies by the usage in a given period. The depreciable basis is after considering the salvage value.

Depreciable basis - same as SL depreciation $ 144,000

Usage Life of the machine 20,000 hours

Machine usage for 2020 780 hours

Depreciation on a per hour basis $ 144,000/ 20,000 = $ 7.2 per hour

Depreciation for 2020 on a usage of 780 hours = 780 * $7.20 = $ 5,616

Computation for requirement (c) - Sum of the years digits for 2021

In a sum of the years depreciation method, the sum of the life of the assets are added and considered as a depreciable life. The salvage value is considered in determining the depreciable basis.

Depreciable basis - same as SL depreciation $ 144,000

Estimated life of the asset 5 years

Sum of the years, (5+4+3+2+1) 15

so the first year depreciation shall be 5/15, the next year 4/15 and so on,

We need to compute the depreciation for 2021 which is the second year, so the formula shall be:

4/15 (remaining useful life) * $ 144,000(depreciable basis) = $ 38,400

Computation for requirement (d) - Double declining balance for 2021

In a double declining balance method the depreciation rate (%) is double that of a straight line method. The subsequent years depreciation is on a reduced balance. No salvage value is considered

The first year's depreciation is calculated

Cost of Machine* (2 * Straight Line depreciation %)

$ 162,900* (2 * 20 %) so the depreciation for 2020 would be

$ 162,900 * 40 % = $ 65,160.

For 2021, which is the requirement in our question, the cost would be the reduced value.

Original Cost of the machine $ 162,900

Double Declining balance Depreciation 2020 $ 65,160

Declining Cost basis for 2021 depreciation $ 97,740

Depreciation @ 40 % $ 39,096