Решение задачи N2829 теория вероятностей

2829. In the urn 3 white, 4 red and 5 blue balls. 3 balls are taken out of the urn. What is the probability that:
1) They are all the same color;
2) Among them are 1 white and 2 red balls?

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