Решение задачи N3795 теория вероятностей полная вероятн

3795. Of the 70 parts, 20 are made in the first workshop, 25 in the second, the rest in the third. The first and third shops make products of excellent quality with a probability of 0.9, the second-0.75. What is the probability that the lucky part will be of excellent quality?

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