Final answer:
The depreciation expense for 2013 is $23,360.
Step-by-step explanation:
To calculate the depreciation expense for 2013, we need to use the units-of-production method. This method calculates depreciation based on the number of miles driven.
First, we need to calculate the depreciation rate per mile. This is done by subtracting the salvage value from the initial cost and dividing by the total estimated miles of useful life. In this case, the depreciation rate per mile would be ($90,000 - $3,600) / 120,000 = $0.73 per mile.
Next, we multiply the depreciation rate per mile by the number of miles driven in 2013. In this case, the depreciation expense for 2013 would be $0.73 * 32,000 = $23,360.