probability that both alternators fail during flight

[lizziegirl]

5.62 A certain airplane has two independent alternators to provide electrical power. The probability that a given alternator will fail on a 1-hour flight is .02. What is the probability that (a) both will fail? (b) neither will fail? (c) one or the other will fail? Show all steps carefully.

 

[daon]

Re: probability

A = event that alt. 1 fails.
B = event that alt. 2 fails.

a) p(A and B) = p(A)p(B|A), but they are independent, so p(B|A)=p(B)

b) See (a), but notice that p(event that alt. 1 won't fail) = 1-p(A)

c) p(A or B) = p(A)+p(B)-p(A and B)

 

[lizziegirl]

You are the best Daon!!!!!!!!

 

[patricia39]

Daon is great! But actually, computing probability is too hard for me- and I've got an idea on how to answer my homework too! But perhaps, I need to double my time on working this alone.

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