Enigma 1351: Let’s face it
13 March 2012
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From New Scientist #2510, 30th July 2005
I took a large wooden cube and painted two of its faces red, two of its faces white, and its two remaining faces blue.
Then I cut up the cube into lots of identically sized smaller cubes and gave them to my niece to play with.
First she counted all the small cubes out loud “One, two, three…”. Then she counted the number of small cubes which had both at least one red face and at least one white face. Then she counted the number of small cubes which had at least one red face and at least one blue face but no white faces.
These last two answers were different but one was the reverse of the other.
How many small cubes have at least one white face but no red faces and no blue faces?
If found a few paper copies of New Scientist while tidying up. This puzzle is from one of them – it doesn’t seem to currently appear in either New Scientist’s or Google Books’ archives.