Question

Tony buys CDs at a music store. You get 20% off the price of a CD. You still have to add 5% sales tax. But you find the sales tax after the discount. So you save money on taxes, too." How much money does Tony save by getting the discount before adding the sales tax? Explain by using expressions.

Answer 1

Lets say a CD costs a 100 dollars (which it obviosly doesn't)

No matter whether we do the discount before or after tax, it'll end up costing 84 dollars to by the CD.

80% of 100 = 80

80 * 1.05 = 84

80% of 105 = 84

The order in which he does the discount and the tax doesn't matter.

Hope this helps.