Answer:
1) 4 x 25m = 100m
2) 0 because after 4 lengths, he's back at the starting block.
3) speed is distance over time so speed here is 100m/125s = 0.8m/s
4) ...
5) 100m / 1.25m/s = 80s
6.a) 100m / 0.5m/s = 200s
7.b) ... can't draw this now..
