   Car on the road or Highway The car is  observed 609/625 in 20 minutes. That means that in 20 minutes of time the probability of not seeing any car is 1-609/625 = 16/625. Let's denot the probability of not seeing any car passin by in 5 minutes as X. The probability of not seeing a car in consecutive two periods of 5 minutes is x**2 and 4 periods of 5 minutes is X**4 which is equal to 20 minutes. X**4 = 16/625 , therefore X = 2/5 And the probability of observing a car in 5 minutes is: 1-X = 3/5 or 60%. Aharon Tam Tuesday, July 8, 2003 i think the approach to the probability in this case would involve careful consideration of the nature of distribution of probability over the time generally we can not assume the probability to be equally distributed over the time.. for the stated probelms we need to consider poison's distribution of probability ..for which the characteristic is ..we canot count the number of failures ie we can only see how many cars passed but not how many did not!! but surely success and failure probabilty put together will always be equal to 1.i dont remember the exact formula but the approach is same. anyway its just a different approach..may be right or not.. reply whatever u think amit Friday, July 11, 2003 ya i m completely agreed to amit, in this problem there must be some other consideration for time because we can't assume an equal distribution of time in cars passing by,so their should be some other solution for this. abhinav saxena Thursday, September 11, 2003 I guess its a good thing we aren't all traveling on the highway. Observing the highway from the side gives you a much better chance of seeing a car then driving on it. Now how can I apply this to the craps table? If the probability of seeing a 7 in 20 minutes is ... Bill Bingham Friday, September 26, 2003 Recent Topics Fog Creek Home