There are 9 black and red stones of same size in a box. If you reach into the box with your eyes close, what is the minimum number of stones you must take out to be sure of having a pair that match?
There are 9 black and red stones of same size in a box. If you reach into the box with your eyes close, what is the minimum number of stones you must take out to be sure of having a pair that match? Correct Answer 10