Given:
a.) A bookstore had 96 copies of magazines yesterday it’s sold 1/4 of them today.
b.) It sold 1/3 of what remained.
Let's determine how many copies of the magazines are left.
Step 1: A bookstore had 96 copies of magazines yesterday it’s sold 1/4 of them today.

Remaining copies = 96 - 24 = 72 magazines
Step 2: It sold 1/3 of what remained.

Remaining copies = 72 - 24 = 58 magazines
Therefore, 58 copies of magazines are left.
The answer is 58.