Answer
The pack of 50 is the better deal
Work Step by Step
We must put both in the same units: dollars per CD. In order to do this, we divide the price of each CD by the number of CDs we get. Thus, we find:
$9.50 \div 30 =.3167$ dollars per CD
$13 \div 50 =.26$ dollars per CD
.26 dollars per CD is less than .3167 dollars per CD, so the pack of 50 is the better deal.
