Find the amount of sales tax collected

Question

A hotel manager found that his gross receipts for the day, including a 9% sales tax, totaled $3,727.80.

Answer 1

Let x = the sales before taxes. Then x*(1.09) = 3727.80. Divide both sides by 1.09 and you get x = 3420.00. Therefore the sales tax is the difference between 3272.8-3420 or $307.80.