If the distance was 200 kilometers and it took 4 hours to cover it then the speed was 200 4 50 kmh kilometers per hour. Sum each speed multiplied by time travelled at that speed and divide this sum of the total traveling time. But speed can change as time goes by.
Remember though that this only applies to constant acceleration in one direction.
Velocity dfrac bigtriangleup distance time velocity time distance. For our example the bikes initial velocity v i is 5 ms. But speed can change as time goes by. Since you end at your beginning location your change in position or distance is actually 0 which means your velocity is also 0.