Solution of problem N3805 probability theory total prob

Solution of problem N3805 probability theory total prob

3805. Parts from three machines arrive in the assembly shop. The first machine gives 5% of marriage, the second - 3%, the third - 2%. What is the probability that a component taken for assembly is standard if 400 parts came from the first machine gun, 500 from the second and 100 from the third?

Additional information:

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