Answer:
Distance: 400 meters
Displacement: zero vector, (0,0)
Explanation:
Distance is a scalar measuring the ground covered during a motion: 400m in this case.
Displacement is the difference between the beginning and end location vectors of an object. Since the track is a closed loop and the walk ends at the same location where it started, the difference in (x,y) coordinates is (0,0), i.e. a zero vector.