This company operates 4 call center in California for customer service. Data on customer calls shows a median duration of 2 minutes, with standard deviation of 60 seconds.

Call center 1 receives on average 10 calls over 30 minutes time span,

call center 2 receives 9 calls over 30 minutes,

call center 3 receives 12 calls over 30 minutes,

call center 4 receives 6 calls over 30 minutes interval.

Customer calls inter arrival times follow exponential distribution.

The call centers are operated independently. What is the average waiting time and total time customer will experience for call center 1.

The call centers are operated independently. What if call center 1 processing time doubles to 4 minutes, what will be average waiting time ?

If the company consolidates the 4 call centers, what will be the average waiting time and total time for customers. (Call center 1 processing time back to 2 minutes)