Double$-$declining$-$balance depreciation

A building acquired at the beginning of the year at a cost of $$103,200$ has an estimated residual value of $$4,100$ and an estimated useful life of $4$ years. Determine

the following.

$($a$)$ The double$-$declining$-$balance rate

$\%$

$($b$)$ The double$-$declining$-$balance depreciation for the first year $