Answer:
d. He can buy 10 CDs
Explanation:
The reason he can only buy 10 is because if the CDs are $9.00 each then you would multiply:
10 x 9 = $90.00
If you add the $30.00 of books:
$90.00 + $30.00 = $120.00
This means he does not have enough money to buy another CD. He has $5.00 left over.