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 (9.3)

b. Use declining-balance depreciation, with a rate that ensures the book value equals the salvage value (9.4)

c. Use double declining balance depreciation (9.4)

d. Use double declining balance, switching to straight-line depreciation (9.5)

e. Use sum-of-years’-digits depreciation (9.A)