Решение задачи N2827 теория вероятностей

2827. In the urn 3 white, 6 red and 5 blue balls. 3 balls are taken out of it at random. What is the probability that: a) they are all the same color; b) they are all different colors; c) among them 1 white and 2 blue balls?

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