Решение задачи N4554 теория вероятностей

4554. From the urn, which contains 7 red, 5 white, 3 black balls, one is chosen at random. What is the probability that the removed ball will be:
1) white (event A)
2) red (event B)
3) blue (event C)

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