Final answer:
The tire shop's total post-tax profit earned last month is $9,926, rounded to the nearest dollar.
Step-by-step explanation:
To find the post-tax profit the tire shop earned last month, we need to calculate the profit first and then subtract the tax. Profit is calculated as revenue minus expenses. In this case, the revenue is $56,409 and the expenses are $45,129. So, the profit is $56,409 - $45,129 = $11,280.
Next, we need to calculate the tax on the profit. The tax is 12% of the profit. So, the tax is 12% of $11,280, which is $1,353.60.
To find the post-tax profit, we subtract the tax from the profit. So, the post-tax profit is $11,280 - $1,353.60 = $9,926.40. Rounded to the nearest dollar, the post-tax profit is $9,926.