George walks to a friend's house. He walks 750 meters North, then realizes he walked too far. He turns around and walks 250 meters South. The entire walk takes him 13 seconds. What is his Velocity

Velocity is given by displacement/time. Let's let the north direction be positive and the south direction be negative. George travels 750 meters and then travels - 250 meters. His displacement is then 750-250, or 500 meters. Divide that by 13 seconds to get 38.5 m/s.