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UKMT Junior Mathematical Challenge, 2026

Combinatorics Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

John is given a $5 \times 5$ array of biscuits as shown. He is told that he can eat these one by one, provided that each time the remaining array has at least one line of symmetry. What is the largest number of biscuits that John can eat?

(A) $5$ (B) $9$ (C) $13$ (D) $17$ (E) $25$

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