Решение задачи N4678 теория вероятностей

4678. There are products of four grades n1=3, n2=4 n3=3, n4=2. M items are taken at random to control. Determine the probability that among them m1=2 is first-class, m2=2, m3=3 and m4=2 are second, third and fourth grades, respectively.

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