Response time at an online site can be modeled with an exponential distribution with a mean service of 5 minutes. John knows this and it is not sure to wait for an answer. What is the probability that for the reply to John's request
(a) What is the probability that the reply to John's request takes longer than 10 minutes?
(b) What is the probability that the reply to John's request takes shorter than 10 minutes?
(c) If the mean service is now 2 minutes, what is the probability that it takes longer than 10 minutes?