- A company purchased a truck on January 1 of the current year for $75,000. Calculate the annual depreciation expense for the trucks life (estimated at 4 years or 145,000 miles, with a salvage value of $15,000). During the trucks 4-year life its usage was: 32,000; 39,000; 40,500; and 41,000 miles. break down in grid form Year 1,year2,year 3, year 4 straight-line totals, units of production total, Double declining balance total. final totals