Answer:
a) The amount of annual depreciation by straight-line method = Cost of the asset - Salvage Value / Number of years in useful life
= ($90,000 - $12,000) / 25 years
= $78,000 / 25 years
= $3,120
Thus, the amount of depreciation under straight-line method is $3,120.
b) Depreciation for first year under double declining balance method = Cost of the asset / Number of years in useful life * 2
= $90,000 / 25 years * 2
= $7,200
Thus, the amount of depreciation for the first year under double declining balance method is $7,200.
Depreciation for second year under double declining balance method = Cost of the asset - First year depreciation / number of years in useful life * 2
= $90,000 - $7,200 / 25 years * 2
= $6,624
Thus, the amount of depreciation for the second year under double declining balance method is $6,624.