Solution of problem N3959 probability theory

Solution of problem N3959 probability theory

3959. Electric bulbs are produced in two factories. The first plant produces 60% of the total number of light bulbs, the second - 40%. The production of the first plant contains 70% of standard lamps, the second - 80%. The store receives products from both plants. What is the probability that the lamp purchased in the store will be standard?

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