Atext book costs $108.00. if mathew paid a total of $113.94 for the book and sales tax, what rate of sales tax was he charged?

Okay. So to find the amount of sales tax, we have to first subtract the text book cost from the total. 113.94 - 108 = 5.94. That’s $5.94 in taxes. To find the percentage, we have to do the amount in taxes divided by the cost of the item, in this case, the textbook. 5.94 / 108 is 0.055. Multiply 0.055 by 100 in order to get the percentage. When you do that, you get 5.5%. Matthew was charged 5.5% in sales tax.