Решение задачи N3900 теория вероятностей полная вероятн

3900. The box contains parts of three types: 40 parts of the first type, 50 parts of the second and 60 parts of the third, with 20, 40, 60% painted among them, respectively. Find the probability that the item extracted from the box is colored at random.

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