Solution of problem N3610 probability theory

Solution of problem N3610 probability theory

3610. Among those entering the assembly of parts from the first machine, 0.21% are defective, from the second - 0.13%, from the third 0.19%, from the fourth 0.1%. Their productivity is 5: 1: 3: 1 respectively. Find the probability that the detail taken at random: 1) is standard; 2) and made on the first machine.

Additional information:

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