Queues in the arrival hall of Terminal Z at Muritala Muhammed Airport are building up rapidly.

Suppose we have 400 international passengers arriving per hour to get through customs. Prior to the introduction of eGates, each passenger was seen by an agent. This took on average 4 mins per passenger. During busy periods, 27 agents were working in parallel to see all passengers.

With the introduction of eGates, the process is split into two steps, such that we now have two queueing systems: one queue for the eGates and one queue for the agents. First, the passenger (queues and) visits an eGate to verify the passenger's identity and submit customs declarations. This verification at the eGate takes on average 3 mins. After that, the passenger still needs to (queue and) see an agent. The verification takes 1 minute on average. An investment has been made for 25 eGates. To compensate for the investment costs of the eGates, only 7 (of the original 27) agents remain on board for the final verification step.

[4.a]Quantify the total time to get through customs (i.e., waiting times plus processing times) before and after the introduction of the eGates.

Prior to the introduction of eGates, the average total time to get through customs is ______________.

With the introduction of eGates, the average total time to get through customs is ______________.

[4.b]Use Little's Law to quantify the impact on the number of passengers in the arrival hall in Terminal 1.

With the introduction of eGates, the number of passengers in the arrival hall will increase/decrease by ______________.