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UKMT Junior Kangaroo, 2025

Algebra Difficulty 2.0 Junior Find the answer United Kingdom

Kirsten wrote numbers in five of the ten circles arranged around a pentagon, as shown in the diagram. She wants to write a number in each of the remaining five circles so that the sums of the three numbers along each side of the pentagon are equal. Which number should she write in the circle marked $X$ ?

(A) $7$ (B) $8$ (C) $11$ (D) $13$ (E) $15$

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