Xavier recently returned from a road trip he took as part of his summer vacation. on his trip away from home, he made two stops to buy gasoline. he first purchased 7 gallons of gasoline for $2.68 per gallon and later on purchased 14 gallons at a price of $2.63 per gallon. on his return trip, he made only one stop for gasoline, purchasing 16 gallons at $3.11 per gallon. what was the average fuel cost per gallon on xavier's summer trip? express your answer rounded to the nearest cent.