During the fall semester, marvin, latoya, and abdulla each read three sevenths of the library books in the classroom. if latoya read 15 books, how many library books are in the classroom?

There are 45 library books in the classroom.

Step-by-step explanation:

The problem says that Marvin, Latoya and Abdulla each read 3/7 of the library books in the classroom.  If Latoya read 3/7 of the books, we can form a proportion to determine the number of total library books in the classroom.  

To solve for 'x', we can either cross-multiply and divide, or we can multiply the denominator by the same factor as the numerator to get a product of 15.  In this case, the same factor would be 5, so 7 x 5 = 35.  If we cross-multiply:

3x = (15)(7) or x = 35.