Since, including sales tax, Alan payed 49.80, and if we subtract 2.40 from 49.80, we can get our sub total. 49.80-2.40=47.40. From there, we can divide our subtotal by 3, since he bought 3 CDs that were the same price. 47.40/3=15.80 Each CD has costed Alan $15.80, not including taxes.