The grocery store has a special deal on potato chips where if you buy 1 bag you get the second bag for 50% off. if the sales tax is 5%, how much is your total purchase for 3 bags of chips if each bag costs 2.50

The price for the three bags of chips is (3 x 2.50) - 2.50/2, because one of the bags will have 50% off. This makes $6.25. Divide this by 100 to find 1%, then multiply by 5 to find 5% - this tells you the amount of sales tax to add on. (6.25/100) x 5 = 0.31 to two decimal places. The final amount for the total purchase is 6.25 + 0.31 = $6.56.