Last month The Sweet Tooth Candy Shops had total sales, including sales tax, of $$54,889.$ The stores are located in a state that has a sales tax of $7\frac{1}{2}\%.($Round your answers to the nearest cent.$)$

$($a$)$ As the accountant for The Sweet Tooth, calculate the amount of sales revenue $($in $$)$ for the shops last month. $

$($b$)$ As the accountant for The Sweet Tooth, calculate the amount of sales taxes $($in $$)$ that must be sent to the state Department of Revenue.

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