Question 1041094
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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 {{{0.08^4}}} = 0.00004096.

The probability that some 3 of 4 engines will fail is {{{C[4]^3*0.08^3}}} = {{{((4*3)/2)*0.08^3}}} = 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%.
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Under the given conditions.