Calculating Units-of-Production Depreciation Swift Trucking Company purchased a long-haul tractor-trailer for $600,000 at the beginning of the year. The expected useful life of the tractor-trailer rig was 8 years or 500,000 miles. Salvage value was estimated to be $80,000. During the first 5 years of use, the rig logged the following usage in miles: Year 1 80,000 miles Year 2 75,000 miles Year 3 80,000 miles Year 4 76,000 miles Year 5 60,000 miles Total 371,000 miles Calculate the depreciation expense to be taken on the tractor-trailer for each year using: (a) Units-of-production method Round your answer to the nearest whole number. Year Depr exp 1 $ 48,000 2 $ 0 3 $ 0 4 $ 0 5 $ 0 Total $ 0 (b) Straight-line method Round your answer to the nearest whole number. Year Depr exp 1 $ 0 2 $ 0 3 $ 0 4 $ 0 5 $ 0 Total $ 0 Which method gives you higher total depreciation charges over the five-year period