Iverson Company purchased a delivery truck for $45,000 on January 1, 2018. The truck was assigned an estimated useful life of 100,000 miles and has a residual value of $10,000. The truck was driven 18,000 miles in 2018 and 22,000 miles in 2019. Compute depreciation expense using the units-of-activity method for the years 2018 and 2019.

Depreciation expense for 2018: $

Depreciation expense for 2019$: $