A building with a cost of $$180,000$ has an estimated residual value of $$36,000,$ has an estimated useful life of $18$ years, and is depreciated by the straight$-$line method.

a$.$ What is the amount of the annual depreciation? Do not round intermediate calculations,

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b$.$ What is the book value at the end of the tenth year of use?

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c$.$ If at the start of the eleventh year it is estimated that the remaining life is $10$ years and that the residual value is $$10,000,$ what is the depreciation expense for each of the remaining $10$ years?

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