Final answer:
Average velocity is the change in position over time. In this scenario, a person walks at 2.0 m/s, then at 6.0 m/s for an equal distance, resulting in a total displacement of zero as they return to the starting point. Consequently, the average velocity for the journey is zero.
Step-by-step explanation:
Average velocity is defined as the displacement divided by the time taken to travel that distance. Displacement measures the change in position from the initial point to the final point. In this case, the person walks at a speed of 2.0 m/s for a certain distance and then at 6.0 m/s for an equal distance. Since the distances are equal, the total displacement is zero. Since the distances covered at both speeds are equal, the person ends up back at the starting point. As a result, the total displacement, which accounts for both magnitude and direction, is zero. Therefore, the average velocity is also zero.