Final answer:
The airplane's average speed from St. Louis to Memphis is 778.29 km/h, calculated by dividing the distance of 2,724 km by the time of 3.50 hours.
Step-by-step explanation:
To find the average speed of the airplane traveling from St. Louis to Memphis, we can use the formula for average speed, which is the total distance traveled divided by the total time of travel. In this case, the airplane travels a distance of 2,724 kilometers in a time of 3.50 hours. The calculation of average speed is as follows:
Average speed = Total distance / Total time
Average speed = 2,724 km / 3.50 h
Average speed = 778.29 km/h
Therefore, the airplane's average speed on this trip is 778.29 kilometers per hour (km/h).