Question: At a certain bus stop, the waiting time of a bus is exponentially distributed of an average of 10 minutes.

a) You arrive at the stop right after a bus leaves. What is the probability you will wait more than 15 minutes for the next bus.

b) Let Y be the number of buses arriving within one hour. What is the distribution of Y?

c) What is the probability that exactly 4 buses arriving within one hour?