John has 36 books in his locker.

He has text books,library books, and telephone books. How many books of each kind does he have if:
lib + tel= 2x text books and
text + tel = 3x lib books

I think it'd be easier to let T,L and B denote text books, library books and telephone books. Then
(1) L + B = 2T
(2) T + B = 3L
We also know
(3) T + L + B = 36
So from (1)
L = 2T - B now substitute into (3) to get
T +2T - B + B = 36 or
3T = 36 so
T = 12, therefore L + B = 24 or L = 24 - B
Then from (2)
12 + B = 3(24 - B) so
12 + B = 72 - 3B and
4B = 60 or B = 15
You should be able to figure out what L is and verify if the answers are correct.

To solve this problem, we can use a system of equations. Let's assign variables to represent the number of text books (T), library books (L), and telephone books (B) that John has.

We are given the following information:
(1) L + B = 2T
(2) T + B = 3L
(3) T + L + B = 36

Let's solve the system step by step:

From equation (1), we can express L in terms of T:
L = 2T - B

Substitute this expression into equation (3):
T + (2T - B) + B = 36
3T = 36
T = 12

Now that we know T = 12, let's substitute this value into equation (1) to find L:
L + B = 2(12)
L + B = 24
L = 24 - B

Substitute the value of T into equation (2):
12 + B = 3L
12 + B = 3(24 - B)
12 + B = 72 - 3B
4B = 60
B = 15

Now that we know B = 15, we can find L:
L = 24 - B
L = 24 - 15
L = 9

So, John has 12 text books, 9 library books, and 15 telephone books.