What's the solution here for question b?

P9.2 (LO 2) In recent years, Freeman 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 below. 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 2019, 24,000; 2020, 36,000; and 2021, 31,000. Instructions a. Compute the amount of accumulated depreciation on each bus at December 31, 2020. b. If Bus 2 was purchased on April 1 instead of January 1, what is the depreciation expense for this bus in (1) 2018 and (2) 2019