An airline company runs a flight that has 10 seats. Each passenger who buys a ticket has a probability p of turning up for the flight. The gender of the passengers is not known until they turn up for a flight, and women buy tickets with the same frequency that men do. The pilot is eccentric and will not fly unless at least two women turn up.

How many tickets should the airline sell to ensure that the expected number of passengers that turn up is greater than 10?