The term "miles per hour" refers to the amount of miles traveled in one hour.
Miles per hour also refers to a measurement of speed, and the formula for calculating speed is distance/time
An example of MPH would be 80 miles per 1 hour -OR- 80 miles/1 hour which really in itself is a fraction. 80/1 = 80 so the vehicle would be traveling 80mph
To solve this problem, we can divide the miles traveled, by the time taken to travel the miles.
So distance/time, 2951/6.5 = 454
The answer to your problem would be that the airplane flies 454 MPH
I hope this helps! Feel free to PM me if you need any more help with these problems. :)