Решение задачи N3982 теория вероятностей

3982. Three machines made did. The first produces 20% of all products, the second - 30%, the third - 50%. The probability that a non-standard will come down from the first machine is equal to 0.05, from the second - 0.03, from the third - 0.01. What is the probability that a randomly selected part will be non-standard?

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