When originaly purchased, a vehicle had an estimased useful life of 9 years. The vehicle cost $57,000 and its estimated residual value is $3,000 After 3 yeats of stroight-vine depreciation, the asset's totat estimoted useful life was revised from 9 years to 4 years and there wos no change iri the estimated residual value. The Depreciation Expense in year 4 is