The answer to the question above is 70.84 cent which is the amount that you will pay the cashier for a candy bar that originally costs 79 cents and is now marked 15% off. This problem can be solved by using the simple percentage principle from mathematics. First, you have to find the marked off-price by multiplying 79 by 85% (1-15%) and then you have to multiply it again by 105.5% (1+5.5%) to obtain the after-sales tax price.