Answer:
The velocity of the boy and the bicycle is 2.2 m/s.
Step-by-step explanation:
We have,
Mass of child is 30 kg and the mass of bicycle is 20 kg. The combined momentum of the child and the bicycle is 110 kg-m/s.
It is required to find the velocity of the boy and the bicycle. The momentum of an object is given in terms of mass and its velocity. So,

M is combined mass of child and bicycle

So, the velocity of the boy and the bicycle is 2.2 m/s.