Question 178526
The probability is 1 in 4,000,000 that a single auto trip in the United States will result in a fatality. Over a lifetime, an average U.S. driver takes 50,000 trips. (a) What is the probability of a fatal accident over a lifetime? Explain your reasoning carefully. Hint: Assume independent events. Why might the assumption of independence be violated? (b) Why might a driver be tempted not to use a seat belt “just on this trip”?
P(A)=1/4000000=0.00000025 
"P(B)=" 50000/4000000=0.0125
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P(A) is correct
P(B) = [1/4 million)]^50,000 because the events are assumed to be independent.
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Assumption may be violated because prob of a accident for an indivisual
changes from adolescence to adult to old age.
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He might say the prob on this trip is so small that caution in not necessary.
Cheers,
Read the book "The Black Swan" by N.N. Taleb to get a new prospective on 
improbable events.
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Stan H.