Решение задачи N3664 теория вероятностей Байеса

3664. In a class 20 girls and 10 boys are trained. To the lesson 4 girls and 3 boys did not complete the task. At random, the called student was unprepared for the lesson. What is the probability that a boy was called to respond?

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