A: All three planes take off at the same time and head west for 45 minutes, making it one-eighth of the way there. At that point, Dan gives 45 gallons of his fuel each to Jen and the engineer. Jen and the engineer press on, and Dan returns to the airport. When they reach the 90 degree mark, Jen gives 45 gallons to the engineer and heads back to the airport; the engineer keeps moving. When the engineer hits the 180 degree mark, Dan leaves the airport heading east and meets the engineer at the 270 degree mark. Dan gives him 45 gallons, turns around, and heads west with the engineer. At the same time, Jen heads east to meet them. They all meet again at the 315 degree mark. Jen gives 45 gallons to Dan and the engineer, leaving each plane with 45 gallons—enough to make it back to the airport.