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UKMT Junior Kangaroo, 2026

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

Eight kangaroos stood in a line, as shown. At some point, two kangaroos standing next to each other and facing each other exchanged places. This was repeated until no further exchanges were possible. How many exchanges were made?

(A) $8$ (B) $10$ (C) $12$ (D) $13$ (E) $17$

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