Question

Jessica purchased a DVD that was on sale for 12% off. The sales tax in her country is 3%. Let Y represent the original price of the DVD. Write an expression that can be used to determine the final cost of the DVD.

Answer 1

Since y is the original cost, let z represent the final cost. So, we set up the expression, (0.12y + y) - 0.03y = z. That shows first the sale, then the tax. From there, we simplify to get 1.12y - 0.03y = z, then simplify it more to get 1.09y = z. We take away the z, and get that the cost, which is 1.09, or 109%, or y (1.09y).