There are three boxes labeled ‘red balls’, ‘White balls’ and ‘red and white balls’. Each of the labels is incorrect. You are allowed to take one ball only from each box. How can you label each box correctly?
(Of course, you are not allowed to look inside!)
Clue for the Puzzle:
It will be sufficient to correctly identify one box. We know that all the boxes are incorrectly labeled. Once one box has been correctly identified, all we need to do is to switch the labels on the other two boxes.
Answer for the Puzzle:
The first thing to do is to take a ball from the box incorrectly labeled ‘red and white balls’. If it is red, then clearly this is the box containing red balls. If white, then white. Since we know that the boxes are all incorrectly labeled it is now sufficient to switch the two remaining labels.