Speed is Distance/Time.
Solving for the man's speed:
Total distance covered by the man is 100meters + 40meters = 140 meters.
Time it takes for the man is 45 seconds..
Therefore, the man's speed is 140meters/45seconds.
Speed = 3.1 meters per second.
Velocity is displacement/time.
displacement is the change in position.
For velocity of man:
Velocity = (100-40)/45
=1.3 meters per second.