CEMC Pascal, 2010

Algebra Difficulty 2.0 Junior Find the answer Canada

In the diagram, each of the five boxes is to contain a number. Each number in a shaded box must be the average of the number in the box to the left of it and the number in the box to the right of it. What is the value of $x$ ?

(A) $28$ (B) $30$ (C) $31$ (D) $32$ (E) $34$

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