Hello forum, I recently lost my notes on this matter, so I hope someone can fill in the gaps in my memory. The problem I am working on is the following: For one ticket window, the waiting time for one people satisfies an exponential distribution λe-λt and expected waiting time is 4 min. a. What’s the probability of the waiting time less than 7 min for 2 persons? b. What’s the probability of the waiting time longer than 165 min for 36 persons? As far as my memory goes: a) P(X>7) = 1 - (1-e^(-0,25*7)) = ... -> for one person However I thought the amount of people influences the result, but I can't remember how.