Consider the attributes of the previous question

FlightN, FromCity, ToCity, FlightDate, DepartureTime, ArrivalTime, TicketN, TicketDate, PassengerName, Cost, Completed, PassengerAddress,

Passenger Age.

Based on the following assumptions:

FlightN is the the key for the FromCity, ToCity, FlightDate, DepartureTime, and ArrivalTime;

Every ticket belongs to only one passenger;

Every passenger may purchase more than one ticket;

Every Ticket may include more than one flight;

Every flight of a ticket together determines the Cost and the attribute

Attribute 'Completed' indicates whether the flight has been completed $($ i$.$e$.$ the passenger has was on the flight$).$

Write all possible dependencies and find a key for all above attributes.