This is very cute puzzle, more like a quick teaser that can be a nice dining table puzzle. I was initially asked this puzzle by a friend of my daughter on her 9th birthday. I rediscovered the problem recently in one of the Martin Gardner books (mathematical puzzles and diversions, Chapter #3, Puzzle #5).
Here it goes:
Imagine that you have three boxes. One containing two black marbles, one containing two white marbles, and the third, one black marble and one white marble. The boxes were labeled for their contents—BB, BW, WW—but someone switched the labels so that every box is now incorrectly labeled. You are allowed to take one marble at a time out of any box, without looking inside, and by this process of sampling you are to determine the contents of all three boxes. What is the smallest number of drawings needed to do this?
As always, please send your answers to firstname.lastname@example.org