how would i solve this?

In recent years, Oriole Transportation purchased three used buses. Because of frequent turnover in the accounting department, a different accountant selected the depreciation method for each bus, and various methods were selected. Information concerning the buses is shown as follows. Salvage Useful Life Depreciation Bus Acquired Cost Value in Years Method 1/1/18 $ 95.200 $ 6.500 4 Straight-line 2 1/1/18 124.000 11,000 4 Declining-balance 1/1/19 89.140 8.500 4 Units-of-activity For the declining-balance method, the company uses the double-declining rate. For the units-of-activity method, total miles are expected to be 126.000. Actual miles of use in the first 3 years were 2019. 24,000: 2020. 33,000; and 2021, 29.000. (a1) For Bus #3, calculate depreciation expense per mile under units-of-activity method. (Round answer to 2 decimal places, e.g. 0.50.) Depreciation expense per mile