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, WW and BW—but
someone has 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?
You can learn the contents of all three boxes by drawing just one marble. The