To answer this question you will find the cost of the columns by multiplying 3.69×4 and get $14.76. The coupon discounts this by 15%, so if you multiply $14.76 by .85, this will be what you are actually paying. The answer to this is $12.55 approximately. I would then subtract $13.30 and $12.55 to get $0.75. This is how much tax you paid. From here I would create an eequation of the percentage time $13.30 =$.75. To solve this take $.75 and divided by $13.30. The answer is about 0.056, which rounds to 0.06. The tax rate was approximately 6%.
