Question $6\mathrm{.}1($Total: $30$ marks$)$

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Oxtongue Limited paid $$135,000$ to purchase equipment at the beginning of $2020.$ Oxtongue Limited estimated the useful life of the equipment to be $4$ years or $200,000$ units. The equipment will be considered fully amortized when the balance in the Accumulated Depreciation account reaches $$120,000.$ The equipment produced $52,000$ units in $2023.$

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Required

$1.$ Determine the estimated residual value of the equipment.

$2.$ What is the amortizable cost of the equipment?

$3.$ Calculate depreciation expense for $2023$ under each of the following methods:

a$.$ straight$-$line

b$.$ units$-$of$-$production

c$.$ double$-$diminishing$-$balance