Solution of problem N3999 probability theory total prob

Solution of problem N3999 probability theory total prob

3999. Of the 25 kinescopes available in a television studio, 5 pcs. produced by plant number 1, 12 pcs. - Plant number 2, and 8 pcs. - Plant number 3. The probability that a kinescope manufactured by factory No. 1 will not fail during the warranty period is 0.95. For a kinescope of plant number 2, this probability is 0.9, and for plant number 3, it is 0.8. Find the probability that at random taken kinescope will withstand the warranty period.

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