Question

A bowl contains 10 red marbles and 10 green marbles. A woman selects marbles at random without looking at them. Assume that the woman does not replace the marbles after drawing them. How many marbles must she select to be sure of having at least three marbles of the same color

Answer 1

5 marbles

Explanation:

Assume the first is color 1

and then the second is color 1

Now the third is color 2

The fourth is color 2

Now the 5th marble of either color will make 3 of one color