Linton Company purchased a delivery truck for $29,000 on January 1, 2017. The truck has an expected salvage value of $1,100, and is expected to be driven 109,000 miles over its estimated useful life of 5 years. Actual miles driven were 12,200 in 2017 and 10,000 in 2018.

Calculate depreciation expense per mile under units-of-activity method.

Compute depreciation expense for 2017 and 2018 using (1) the straight-line method, (2) the units-of-activity method, and (3) the double-declining-balance method.