Okay, so the first thing you need to do is find the difference.
64.19 - 59.99 = 4.20
So the percentage is determined by dividing that difference by the cost of the item originally:
4.20 / 59.99 = about .07
Next, you change this number to a percentage by moving the decimal to the right two spaces, so that would be 7%.
Therefore, the sales tax in the area is 7%.