Solution of problem N2597 probability theory total prob

Solution of problem N2597 probability theory total prob

2597. At the first plant, for every 100 light bulbs, an average of 90 standard ones are made, on the second - 95, on the third - 85, and their products are respectively 50%, 30%, 20% of all light bulbs supplied to stores in the area. Find the probability of acquiring a standard light bulb.

Additional information:

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