Final answer:
If both lavatories are in use on an aircraft's forward area and a passenger arrives, they will have to wait until one of the lavatories becomes available. The passenger will be handled by joining a queue or waiting area designated for such circumstances.
Step-by-step explanation:
In an aircraft's forward area with 2 lavatories, passengers arrive on average every 10 minutes. If both lavatories are in use and a passenger arrives, they will have to wait until one of the lavatories becomes available. In this scenario, the passenger will be handled by joining a queue or waiting area designated for such circumstances. Once a lavatory becomes available, the next passenger in line will be able to use it.