An airline determines that passengers who book a seat on their aeroplanes fail to arrive 1/15 of the time, independently of other passengers. Therefore, it books more people than seats. It books 20 people for Aircraft A, which has 19 seats; and it books 40 people for Aircraft B, which has 38 seats. Showing all working, which aircraft is more likely to be oversold: that is, to have more passengers than seats on the day of the flight.