In recent years, Novak 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 summarized as follows. For the declining-balance method, the company uses the double-declining rate. For the units-of-activity method, total miles are expected to be 115,000. Actual miles of use in the fist 3 years were 2019,23,000; 2020,31,000; and 2021,30,500. (a1) For Bus \#3, calculate depreciation expense per mile under units-of-activity method, (Round onswer to 2 decimal places, es. 0.50) Depreciation expense $ per mile