Oriole Bus Lines uses the units-of-activity method in depreciating its buses. One bus was purchased on January 1, 2025, at a cost of $125,000. Over its 4-year useful life, the bus is expected to be driven 220,000 miles. Salvage value is expected to be $8,400. (a) Compute the depreciation cost per unit. (Round answer to 3 decimal places, e.g. 6.251.) Depreciation cost per unit $