A company purchases a delivery van for $24,000. The van is estimated to have a four-year service life and a residual value of $2,400. During the four-year period, the company expects to drive the van 120,000 miles. Required: Calculate annual depreciation for the four-year life of the van using each of the following methods. Straight-line Double-declining-balance Activity-based (Actual miles driven each year were 19,000 miles in Year 1; 30,000 miles in Year 2; 22,000 miles