The speed of the ride is
Speed = (distance covered) / (time to cover the distance)
Speed = (4,000 m) / (45 min)
Speed = 88.89 m/s
Speed = 1.481 m/s
Speed = 5.333 km/hr
There's not enough information given in the question to calculate the velocity of the ride. For example ...
-- If the ride was completely in a straight line, then the velocity would be exactly equal to the speed.
-- If the rider went 2km from his house and then 2km back home again, his velocity for the whole ride would be zero.
We just don't know from the information given.