Grant had 36 books in his locker. some were library book, some were textbooks, and the rest were free reading books. the number of library books and the free reading books combined equals twice the number of textbooks. the number of textbooks and free reading books combined equals three times the number of library books. how many of each type of a grant’s locker?

Total number of books = 36

Let the number of library books be = x

Let the number of textbooks be = y

Let the number of free reading books be = z

..... (1)

As mentioned, number of library books and the free reading books combined equals twice the number of textbooks, equation is  .......(2)

The number of textbooks and free reading books combined equals three times the number of library books, equation is ... (3)

Putting the value of x+z from equation (2) in (1)

Putting the value of y+z from equation (3) in (1)

As,

Hence, Grant has 9 library books, 12 textbooks and 15 free reading books.