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CEMC Gauss (Grade 7), 1998

Combinatorics Difficulty 3.0 AMC 10/12 Find the answer Canada

Each of the 12 edges of a cube is coloured either red or green. Every face of the cube has at least one red edge. What is the smallest number of red edges?

(A) $2$ (B) $3$ (C) $4$ (D) $5$ (E) $6$

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