The time (in minutes) between arrivals of customers to a post office is to be modelled by the Exponential distribution with mean . Please give your answers to two decimal places.

Part a)

What is the probability that the time between consecutive customers is less than 15 seconds?



Part b)

Find the probability that the time between consecutive customers is between ten and fifteen seconds.



Part c)

Given that the time between consecutive customers arriving is greater than ten seconds, what is the chance that it is greater than fifteen seconds?

You can earn partial credit on this problem.