CEMC Cayley, 2010

Number theory Difficulty 2.0 Junior Find the answer Canada

The odd numbers from 5 to 21 are used to build a 3 by 3 magic square. (In a magic square, the numbers in each row, the numbers in each column, and the numbers on each diagonal have the same sum.) If 5, 9 and 17 are placed as shown, what is the value of $x$ ?

(A) $7$ (B) $11$ (C) $13$ (D) $15$ (E) $19$

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