Ebra Allen purchased a used tractor for $70,000. Before the tractor could be used, it required new tires, which cost $4,400, and an overhaul, which cost $5,600. Its first tank of fuel cost $300. The tractor is expected to last six years and have a residual value of $8,000. Determine the cost and depreciable cost of the tractor and calculate the first year’s depreciation under the straight-line method.