View Full Version : Probability of having a fatal car accident?

04-12-2008, 04:40 PM
Is this correct?

1 in 4,000,000 trips results in a fatality
if you take 50,000 trips what is the probability of having a fatal accident?

3,999,999/4,000,000 ^ 50,000 is 0.98758
1-.98758 is .012 or 1.2%

Additionally, the problem asked us to assume independent events. Why might the assumption of independance be violated? Is this because you can not possibly have more than 1 fatal car accident in a single lifetime?

Thanks in advance for any help with this problem :o)

04-12-2008, 08:40 PM
I like your solution, but only because the question is ambiguous. It does NOT state that the driver is the victim. It states only that there is a fatality.

If the driver is the fatality, then I would expect survival of 49,999 and non-survival in one (1).

\left(\frac{3999999}{4000000}\right)^{49999}*\frac {1}{4000000} This is a very small probability since the death must be EXACTLY on the 50,000th trip.

You keep pondering the independence. I think you are on the right track.