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UKMT Junior Kangaroo, 2024

Combinatorics Difficulty 2.0 Junior Find the answer United Kingdom

Mabel wants to colour each of the nine line segments shown in the diagram red, blue or green. The sides of every triangle should be coloured with three different colours. She has already coloured three of the segments, as shown. What colour can the line segment marked $x$ be coloured?

(A) only blue (B) only green (C) only red (D) any of red, blue or green (E) such a colouring is not possible

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