Company purchased a delivery van on January 1, 2016, for $45,000. The equipment was expected to remain in service 4 years (or 100,000 miles) and has a residual value of $5,000. The van traveled 30,000 miles the first year, 25,000 miles the second year, and 22, 500 miles in the third and fourth year. Please calculate the depreciation expense per year for all four years of the asset's life using the (a) straight-line method; (b) units-of-production method; (c) double declining balance method; (d) sum of the years digit method