WAEC Agricultural Science 2023 Question 46

Study the table below.
Cost price N20,000; useful life Y years; salvage value N5,000; annual depreciation N1,000/annum; total depreciation N15,000
Cost price N60,000; useful life 10 years; salvage value N18,000; annual depreciation N4,200/annum; total depreciation Z
The useful life represented by Y in the illustrated table is

1. A.3 years.
2. B.4 years.
3. C.15 years.
4. D.20 years.