Answer and Explanation:
The computation of the depreciation expense for 2017 and 2018 under the following methods
a. Straight-line method
= (Purchase cost - residual value) ÷ (estimated life)
= ($400,000 - $100,000) ÷ (5 years)
= $60,000
Since the depreciation expense under this method would remain the same for the remaining useful life
So for 2017 and 2018, the depreciation expense i.e. $60,000 would be charged every year.
b. Under the sum-of-the-year-digits method
For 2017,
= ($400,000 - $100,000) × 5 years ÷ ( 5 + 4 + 3 + 2 + 1)
= $300,000 × 5 years ÷ 15 years
= $100,000
For 2018, the book value is
= $400,000 - $100,000
The $100,000 is the depreciation expense of 2017 year
= $300,000 × 4 ÷ 15
= $80,000
