Решение задачи N3274 теория вероятностей

3274. In the urn there are 25 balls of the same size and appearance: among them 5 are white and 20 are black. 6 balls are taken at random (without returning to the urn). What is the probability that among them will be 3 white?

Detailed solution. Decorated in Microsoft Word 2003 (Quest decided to use the formula editor)