Решение задачи N3849 теория вероятностей Байеса

3849. Of the parts received for assembly, 70% are made by an automatic machine, which gives 2% of scrap, and 30% - by an automatic device, which gives 5% of scrap. A piece taken at random was defective. Find the probability that it is made the first machine.

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