A tractor for over-the-road hauling is purchased for $90,000. It is expected to be of use to the company for 6 years, after which it will be salvaged for $4,000. Calculate the depreciation deduction and the unrecovered investment during each year of the tractor's life.
a) Use straight-line depreciation.
b) Use declining balance depreciation using a rate that ensures the book value equals the salvage value.
c) Use double declining balance depreciation.
d) Use double declining balance switching to straight line depreciation.