Answer:
Before her donation, Marie owned 35 comic books.
Explanation:
Marie donated 40% of her comic books to a school, that is, Marie donated 40 comic books per 100 comic books she owned. We can write it as a ratio: the ratio of donated comic books to total comic books is 100:40. If she donated 14 comic books, the number of comic books she owned before her donation were:
14 donated cb × (100 total cb/40 donated cb) = 35 total cb