To find the total amount Mary spent after tax, you will calculate the price before tax and then find the amount after the tax has been included.
1. $30 + $35 = $65
2. $65 x 1.07 = $69.55 (We multiplied by 1.07, because 1 is the whole price and the 0.07 represents the part that is the tax).
Mary's total cost after tax was $69.55.