Experience the Tour de France (ETF) is a specialty travel agent. They arrange vacations for amateur cyclists who want to experience the Tour de France by riding through one or more stages in the race. They have 4 people who take calls from clients. Each call lasts on average 25 minutes with a standard deviation of 50 minutes. A call arrives on average every 20 minutes with a standard deviation of 20 minutes.
(Round your answer to 2 decimal places.)
On average, how many minutes does a caller wait before talking to an agent?

The standard deviation for the call time is 50 minutes while the average call duration is 25 minutes. The caller has to wait for sometime before the agent answers it because they have 4 agents who take up the calls from the clients. A call arrives every 20 minutes with a standard deviation of 20 minutes. In the given scenario the waiting time can be calculated using the formula below:

t = ( Ф * standard deviation + average call duration * standard deviation )

Solving the equation we get 18 minutes.