Depreciation by Units-of-activity Method Prior to adjustment at the end of the year, the balance in Trucks is $412,600 and the balance in Accumulated Depreciation-Trucks is $129,220. Details of the subsidiary ledger are as follows: Estimated Estimated Accumulated Depreciation Miles Operated Truck Residual Useful at Beginning During No. Cost Value Life of Year Year 1 $80,000 $12,000 220,000 miles 33,000 miles 2 118,100 14,172 360,000 $23,620 36,000 3 104,500 14,630 208,000 83,600 20,800 4 110,000 13,200 400,000 22,000 48,000