A process flow map for a call center is provided below. Here's how this process works. Customers with questions about this company's products call an $800$ number. During a typical $8-$ hour day shift, the time between calls can be approximated by an exponential distribution with a mean of $4$ minutes. The call center has $10$ phone lines and hence can handle up to $10$ calls at once. If a call arrives and all $10$ lines are in use, then the caller gets a busy signal and has to call back later. If a call arrives and fewer than $10$ lines are in use, then the call goes directly to a customer service $($CS$)$ person, if one is available, and otherwise is put on hold. The amount of time for a CS person to handle a call, once answered, can be approximated by a normal distribution, with a mean of $10$ minutes and a standard deviation of $2$ minutes. Note: Because there are only $10$ phone lines, the number of CS people plus the capacity of Line must be $10.$ Process Flow Map for Call Center