A box contains 12 marbles of three different colors – Green, Yellow and Blue – 4 of each.
If you were to close your eyes and pick them at random, how many marbles must you take out to be sure that there are at least two of one color among the marbles picked out ?
You would have to draw atleast four. If draw one of each of the three colors the fourth one would have to be a match to one of the previous colors drawn. Any number under four has a chance of being different colors.