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CEMC Galois, 2007

Combinatorics Difficulty 3.0 AMC 10/12 Prove it Canada

A (2k+1)(2k+1) by (2k+1)(2k+1) by (2k+1)(2k+1) cube, where kk is a positive integer, is painted in the same manner as the 55 by 55 by 55 cube with white squares in the corners. Again, the cube is cut into 11 by 11 by 11 cubes. (i) In terms of kk, how many of these cubes have exactly two white faces? Explain how you obtained your answer. (ii) Prove that there is no value of kk for which the number of cubes having at least two white faces is 20062006.

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