Question

An aircraft has three engines $$A,\,B$$  and $$C$$. The aircraft crashes if all the three engines fail. The probabilities of failure are $$0.03,\,0.02$$   and $$0.05$$  for engines $$A,\,B$$  and $$C$$ respectively. What is the probability that the aircraft will not crash ?

A. $$0.00003$$
B. $$0.90$$
C. $$0.99997$$  
D. $$0.90307$$
Answer :   $$0.99997$$
Solution :
Since, probabilities of failure for engines $$A,\,B$$  and $$C\,P\left( A \right),P\left( B \right)$$    and $$P\left( C \right)$$  are $$0.03,\,0.02$$   and $$0.05$$  respectively.
The aircraft will crash only when all the three engine fail.
So, probability that it crashes
$$\eqalign{ & = P\left( A \right) \times P\left( B \right) \times P\left( C \right) \cr & = 0.03 \times 0.02 \times 0.05 \cr & = 0.00003 \cr} $$
Hence, the probability that the aircraft will not crash $$ = 1 - 0.00003 = 0.99997$$

Releted MCQ Question on
Statistics and Probability >> Probability

Releted Question 1

Two fair dice are tossed. Let $$x$$ be the event that the first die shows an even number and $$y$$ be the event that the second die shows an odd number. The two events $$x$$ and $$y$$ are:

A. Mutually exclusive
B. Independent and mutually exclusive
C. Dependent
D. None of these
Releted Question 2

Two events $$A$$ and $$B$$ have probabilities 0.25 and 0.50 respectively. The probability that both $$A$$ and $$B$$ occur simultaneously is 0.14. Then the probability that neither $$A$$ nor $$B$$ occurs is

A. 0.39
B. 0.25
C. 0.11
D. none of these
Releted Question 3

The probability that an event $$A$$ happens in one trial of an experiment is 0.4. Three independent trials of the experiment are performed. The probability that the event $$A$$ happens at least once is

A. 0.936
B. 0.784
C. 0.904
D. none of these
Releted Question 4

If $$A$$ and $$B$$ are two events such that $$P(A) > 0,$$   and $$P\left( B \right) \ne 1,$$   then $$P\left( {\frac{{\overline A }}{{\overline B }}} \right)$$  is equal to
(Here $$\overline A$$ and $$\overline B$$ are complements of $$A$$ and $$B$$ respectively).

A. $$1 - P\left( {\frac{A}{B}} \right)$$
B. $$1 - P\left( {\frac{{\overline A }}{B}} \right)$$
C. $$\frac{{1 - P\left( {A \cup B} \right)}}{{P\left( {\overline B } \right)}}$$
D. $$\frac{{P\left( {\overline A } \right)}}{{P\left( {\overline B } \right)}}$$

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Probability


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