A router receives packets from two applications. The time between the generation of consecutive
 packets of application 1 and application 2 are exponential variables with rate λ1 and λ2, respectively. The service
 time of the router is an exponential variable with rate µ.
-  Assume 1 packet (packet A) is in the buffer (and is being served) at time 0. After tB seconds, a new packet
 
(packet B) arrives in the buffer. Find E[tB].
-  Compute the average permanence time of packet B in the buffer (waiting time plus transmission).
 
-  Define T as the time when the last bit of the next packet arrived in the buffer is transmitted by the router.
 
Find E[T].