I tried to understand the following concept but a friend of mine came up with a different result. Can someone explain how I would find the odds of the following: I have a large box full of marbles. It is full of a total of 100 marbles: 15 blue marbles, 15 purple marble, 15 rainbow marbles, 15 orange marbles, 15 yellow marbles, 15 red marbles, and 10 multicolor marbles. My friend randomly pulls one marble out of the box. If I randomly pull 4 marbles out of the box, what are the odds that one of the marbles will be the same marble that he pulled out? Also, please NOTE, consider the marbles to automatically replenish. Therefore, there are always the same amount of each marble.. even after my friend pulls one out.