Your calculation of George's SPEED is correct. Nice work !
Velocity is different. Here's how to do velocity:
Velocity = (displacement) / (time)
Displacement = (distance and direction from start-point to end-point)
George ended 500 meters North of where he started. So his displacement is 500 meters North.
Velocity = (500 meters North) / (13 seconds)
Velocity = 38.46 m/s North