What is the velocity of a bike

the bike is going 50 meters every 15 seconds

Simple distance/time calculation
v = d/t
v = 50/15
v = 3.33 m/s

Velocity can not be determined unless you mention the direction.
However the speed is distance/time = 50m/15s = 10m/3s = 3.33 metesr per second.

Simple distance/time calculation
v = d/t
v = 50/15
v = 3.33 m/s

You can calculate like this
v = d/t
v = 50/15
v = 3.33 m/s