Решение задачи N4664 теория вероятностей

4664. There are products of four grades, and the number of products of each grade is, respectively, 3, 2, 3, 2. For control, 7 products are taken at random. Determine the probability that among them 2 is a first-class item, 1 is a second-grade item, 3 is a third-grade item, and 1 is a fourth-grade item.

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