Решение задачи N3275 теория вероятностей

3275. In the urn there are 20 balls of the same size and appearance: among them 8 are white and 12 are black. 7 balls are taken at random (without returning to the urn). What is the probability that 6 whites will be among them?

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