Explanation:
just as the graph shows.
no trick or hidden meaning or whatever.
#1
0 seconds to 5 seconds.
0 meters to 3 meters.
traveled 3-0 = 3 meters in 5-0=5 seconds
#2
0 seconds to 8 seconds.
0 meters to 5 meters.
traveled 5-0=5 meters in 8-0=8 seconds.