well first of all you need to divide 8.40 by to to get 4.20 the you multiplie it by 3 to get 12.60 the you need to take 4.20 and divid it by 2 again for the .5 to get 2.10 the add it to the 12.60 to get 14.70 and there you have your answer which is $14.70
