Answer:
The art teacher needs to buy at least 8 packs of 8 brushes.
Explanation:
Every pack has 8 brushes. She needs AT LEAST 60 so she cannot have less than 60 brushes but can have more than 60. 8 x 8 =64 so she would have 4 bushes left over. She needed to buy 8 packs so she can have at least 60.