Answer:
4 years
Explanation:
For calculation of remaining useful life of the plant asset first we need to find out the Straight Line Depreciation (annual), useful life and life end which is shown below:-
Straight Line Depreciation (annual) = (Cost – Salvage Value) ÷ Useful Life
$10,000 = ($80,000 - $20,000) ÷ Useful Life
$10,000 × Useful Life = $80,000 - $20,000
Useful Life = ($80,000 - $20,000) ÷ $10,000
Useful Life = 6 years
Life ended = Accumulated Depreciation ÷ Annual Depreciation
= $20,000 ÷ $10,000
= 2 years
Remaining Useful Life = Useful life - Life ended
= 6 years - 2 years
= 4 years