Решение задачи N4660 теория вероятностей

4660. There are products of four grades, and the number of products of each grade is, respectively, 2, 2, 4, 2. For control, 5 products are taken at random. Determine the probability that among them 1 is a first-class item, 1 is a second-grade item, 1 is a third-grade item, and 2 is a fourth-grade item.

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