Answer: 7920
Explanation:
Convert 600mph to feet per hour.
600 x 5280 = 3168000 feet per hour
Convert feet per hour into seconds by dividing by 60 to get minutes and 60 again to get seconds.
3168000 / 60 / 60 = 880 Feet per second
Multiply by 9
880 x 9 = 7920 feet in 9 seconds