Degreciation by Units-of-activity Method Prior to adjustment at the end of the yea, the balance in Trucks is $419,600 and the balance in Accumulated Depreciation-Trucks is $123,120. Details of the subsidiary ledger are as follows: a, Determine for each truck the depreciation rate per mile and the amount to be credited to the accumulated depreciation section of each subsidiary acceunt 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. b. Journalize the entry on December 31 to record depreciation for the year, if an amount box does not require an entry, leave it blank