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UKMT Pink Kangaroo, 2020

Algebra Difficulty 2.0 Junior Find the answer United Kingdom

Freda wants to write a number in each of the nine cells of this figure so that the sum of the three numbers on each diameter is $13$ and the sum of the eight numbers on the circumference is $40$ . What number must be written in the central cell?

(A) $3$ (B) $5$ (C) $8$ (D) $10$ (E) $12$

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