Write a system of equations to describe the situation below, solve using any method, and fill in the blanks.

Jerry and Malia, both teachers, are adding books to their class libraries. Jerry's classroom started out with a collection of only 12 books, but he plans to purchase an additional 4 books per week. Malia's library started out with 36 books, and she has enough money in her budget to purchase another 1 book per week. At some point, the two teachers' libraries will contain the same number of books. How many books will each class have? How many weeks will that take?

The two teachers' libraries will each have ____ in ____ weeks.