Problema Solution
a. at a subway stop, a train arrives every six minutes, waits one minute, and then leaves. if you arrive at a random time, what is the probability there will be a train waiting?
b. if you arrive and there is no train waiting, what is the probability that you will wait no more than two minutes before one arrives?
Answer provided by our tutors
a. In every 7 minutes(6+1), there is a train for 1 minute. So the probability is 1/7.
b. If there was no train, you must have arrived in one of the other 6 minutes. A train will arrive in 2 minutes if you arrived within the last 2 minutes of the 6, so the probability is 2/6 or 1/3.