George drives to a friend's house. He drives 850 meters north before he realizes he went too far. He reverses 250 meters south and stops. The entire drive takes 25 seconds. What is George's average velocity, in m/s? Hint: Velocity does not use total distance. To get the correct answer... you will need to type the calculated answer, the unit, and the direction. Use the format: all lower case: number unit direction (with a single space between each.) There must be a single space between and all in lower case.