Решение задачи N3796 теория вероятностей полная вероятн

3796. Of the 80 parts, 18 were made in the first workshop, 20 in the second, and the rest in the third. The first and third workshops give products of excellent quality with a probability of 0.9, and the second with a probability of 0.6. What is the probability that the item taken at random will be of excellent quality?

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