P$9\mathrm{.}2($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.

$\backslash$table$[[$Bus$,$Acquired,Cost,$\backslash$table$[[$Residual$],[$Value$]],\backslash$table$[[$Useful Life$],[$in Years$]],$Depreciation Method$],[1,\frac{1}{1}\frac{?}{18},\frac{?}{\text{b}\text{a}\text{r}}(96,000),6,000,5,$Straight$-$line$],[2,\frac{1}{1}\frac{?}{18},140,000,10,000,4,$Declining$-$balance$],[3,\frac{1}{1}\frac{?}{19},92,000,8,000,5,$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 $120,000.$ 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 $(2)2019?$