Depreciation by units-of-activity Method Prior to adjustment at the end of the year, the balance in Trucks is $403,400 and the balance in Accumulated Depreciation—Trucks is $121,380. Details of the subsidiary ledger are as follows: Truck No. Cost Estimated Residual Value Estimated Useful Life Accumulated Depreciation at Beginning of Year Miles Operated During Year 1 $77,000 $11,550 240,000 miles — 36,000 miles 2 115,400 13,848 360,000 $23,080 36,000 3 93,500 13,090 216,000 $74,800 21,600 4 117,500 14,100 280,000 $23,500 33,600 a. Determine for each truck the depreciation rate per mile and the amount to be credited to the accumulated depreciation section of each subsidiary account for the miles operated during the current year. Keep in mind that the depreciation taken cannot reduce the book value of the truck below its residual value. Round the rate per mile to two decimal places. Enter all values as positive amounts.