Final answer:
The average speed of the airplane is 800 mi/h.
Step-by-step explanation:
To calculate the average speed of the airplane, we need to divide the total distance travelled by the time taken to complete the journey.
Given that the distance of the journey was 2,840 mi and the airplane took 3 hours and 33 minutes (or 3.55 hours), we can use the formula: Average Speed = Distance / Time.
Therefore, the average speed of the airplane is 2,840 mi / 3.55 hours = 800 mi/h.