A box contains 12 marbles of three different colors. Green, yellow and blue- 4 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?


Answer:

In the first three pickings you may get 1 of each color. in the 4 th pick there will be at least two of one color.
So, the answer is 4.