Answer:
depreciation recorded by December 31, 2015=$4,333.33
Step-by-step explanation:
The expression for the depreciable cost is as follows;
depreciable cost=Acquisition cost-salvage value
where;
acquisition cost=$42,000
residual value=$3,000
replacing;
depreciable cost=42,000-3,000=$39,000
depreciable cost=$39,000
The annual depreciation can be expressed as;
annual depreciation=depreciable cost/estimated useful life
where;
depreciable cost=$39,000
estimated useful life=3 years
replacing;
annual depreciation=39,000/3=13,000
annual depreciation=$13,000
depreciation between October 1 and December 31=(4/12)×13,000=$4,333.33
depreciation recorded by December 31, 2015=$4,333.33