If it is 20% off, we multiply the decimal form of 20%(0.2) to 13. 0.2 x 13 equals 2.6, and we subtract 13 by this to get 10.4. 10.4 is the price of the CD after the 20% off, so now we need to figure out the price after tax. Since tax is 6%, we can multiply the decimal form of it(0.06) to the discounted price. 10.4 x 0.06 equals 0.624, and 10.4 + 0.624 equals 11.024. So the total price of the CD including the discount and tax is $11.024.
:)