Concord Company purchased equipment for $$228,400$ on October $1,2025.$ It is estimated that the equipment will have a useful life

of $8$ years and a salvage value of $$12,400.$ Estimated production is $40,000$ units and estimated working hours are $20,000.$ During $2025,$

Concord uses the equipment for $500$ hours and the equipment produces $1,000$ units.

Compute depreciation expense under each of the following methods. Concord is on a calendar$-$year basis ending December $31.($Round

rate per hour and rate per unit to $2$ decimal places, e$.$g$.5\mathrm{.}35$ and final answers to $0$ decimal places, e$.$g$.45,892.)$

$($a$)$ Straight$-$line method for $2025$

$($b$)$ Activity method $($units of output$)$ for $2025$$

$($c$)$ Activity method $($working hours$)$ for $2025$$

$($d$)$ Sum$-$of$-$the$-$years'$-$digits method for $2027$$

$($e$)$ Double$-$declining$-$balance method for $2026$$

please help me with part D $($Sum of the years' digits for $2027)$ and part E $($Double declining balance for $2026)$