Answer:
a. Company B's depreciation expense for 2021 is $12,800
b. Accumulated Depreciation (Dr.) $23,800
Plant and equipment (Cr.) $23,800
Explanation:
The depreciation expense of 2021 will be $12,800. The cost of plant and equipment is $125,000.
Depreciation 2018 : $125,000 * 10% = 12,500 * 2 = $25,000
2019 : $125,000 - $25000 = $100,000 * 10% * 2 = $20,000
2020: $100,000 - $20,000 = $80,000 * 10% * 2 = $16,000
2021 : $80,000 - $16,000 = 64,000 * 10% * 2 = $12,800