For the declining-balance method, the company uses the double-declining rate. For the units-of-activity method, total miles are expected to be 120,000. Actual miles of use in the first 3 years were 2016, 24,000; 2017, 35, 500; and 2018, 32,000. For Bus #3, calculate depreciation expense per mile under units-of-activity method. Compute the amount of accumulated depreciation on each bus at December 31, 2017. If Bus 2 was purchased on April 1 instead of January 1, what is the depreciation expense for this bus in (1) 2015 and (2) 2016