SOLUTION: A commercial jet aircraft has four engines. For an aircraft in flight to land safely, at least two engines should be in working condition. Each engine has an independent reliabilit

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Question 1041094: A commercial jet aircraft has four engines. For an aircraft in flight to land safely, at least two engines should be in working condition. Each engine has an independent reliability of 92%. What is the probability that the aircraft will land safely?
Found 2 solutions by ikleyn, robertb:
Answer by ikleyn(52788) About Me  (Show Source):
You can put this solution on YOUR website!
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A commercial jet aircraft has four engines. For an aircraft in flight to land safely, at least two engines should be
in working condition. Each engine has an independent reliability of 92%. What is the probability that the aircraft will land safely?
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The probability that all 4 engines will fail is 0.08%5E4 = 0.00004096.

The probability that some 3 of 4 engines will fail is C%5B4%5D%5E3%2A0.08%5E3 = %28%284%2A3%29%2F2%29%2A0.08%5E3 = 0.003072.


Thus the probability that the fatal event will happen (4 or 3 engines will fail) is 0.00004096 + 0.003072 = 0.00311.


The probability that the aircraft will land safely = 1 - 0.00311 = 0.9969 = 99.69%.

Under the given conditions.


Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
Let the random variable X = # of engines in working condition.
The possible values of X: 0, 1, 2, 3, 4.
==> ,
the probability that the aircraft will land safely.