posted by Bob .
A newly designed international airport is planning to label its gates. Each gate must be assigned a letter from the alphabet from A to M (13 in all), and a number from 1 to 15. To avoid confusion, any two gates must be assigned a different letter, or a different number (or both). What is the maximum number of distinct gates that the airport can have?
Math (Combinatorics) -
looks to me like just 13*15 possible gate id's.