3769. The warehouse receives the products of three factories, the first of which produces 40% of all products, the second - 50%, the third - 10%. In the production of the first factory, 80% of products of the highest grade, the second - 50%, the third - 20%. Determine the probability that a product taken at random from the warehouse will be of the highest grade.

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