Time between incoming calls to a help desk can be seen as a Poisson distributed random variable with average 3 min and the duration can be seen as a discrete random variable as in table $2. Table $1 shows a cumulative distribution of incoming calls (made from a Poisson distribution) and Make a monte carlo simulation for the first 10 calls arriving.

What is the approximate waiting time for one customer, how long will all 10 calls take? What is the average duration of each call.