Answer: x > 5.
Explanation:
The information given in the question can be expressed in an equation as:
Let the cost of each book be x
Cost of mug + Cost of books > 24
9 + (3 × x) > 24
9 + 3x > 24
3x > 24 - 9
3x > 15
x > 5.
Therefore, each book cost more than $5.