A network carrier serves 39 spoke cities from a single hub. How many city-pairs does it serve? (A city-pair is City A to City B. City A to City B and City B to City A are consider just one city-pair)
This same airline adds a 40th spoke city to its network using a 100 seat capacity aircraft. On a flight from this 40th spoke to the hub, how many passengers, on average, does it need to attract to each destination to achieve an 80% load factor?