please help with this I'm not sure what the answer is

Ok so first just pay attention to the Mystery books and Science books.
there are 13 mystery books and 15 Science books so your answer will be two.
Hope this helps.
each box has 15 science fiction and 13 mystery with a total of 28 books per box. If there are 7 boxes so there should be 28*7=196 books. So for each kind of book do 15 * 7 and 13 * 7 to get 105 science and 91 mystery books all together for a total of 196 books.