Perdue Company purchased equipment on April $1$ for $$59,940.$ The equipment was expected to have a useful life of three years, or $4,860$ operating hours, and a residual value of $$1,620.$ The equipment was used for $900$ hours during Year $1,1,700$ hours in Year $2,1,500$ hours in Year $3,$ and $760$ hours in Year $4.$

Required:

Determine the amount of depreciation expense for the years ended December $31,$ Year $1,$ Year $2,$ Year $3,$ and Year $4,$ by $($a$)$ the straight$-$line method, $($b$)$ units$-$of$-$activity method, and $($c$)$ the double$-$declining$-$balance method.