Final answer:
The airplane's average speed, or unit rate for kilometers per hour, is 712 km/h, calculated by dividing the total distance traveled, 6,408 kilometers, by the total time of the flight, 9 hours.
Step-by-step explanation:
The unit rate for kilometers per hour (km/h) is calculated by dividing the total distance traveled by the time it took to travel that distance. In this case, an airplane traveled 6,408 kilometers in 9 hours.
The airplane's unit rate for kilometers per hour is 712 km/h.
To calculate the unit rate, which is the average speed of the airplane, we use the formula:
average speed = distance / time
By substituting the given values into the formula, we get:
average speed = 6,408 km / 9 h = 712 km/h