Answer:
110 kg
Step-by-step explanation:
The momentum of the Malcom+motorcycle system is given by:

where
(m+M) is the total mass of the system, with
m = mass of Malcom
M = 190 kg (mass of the motorcycle)
v = 20 m/s velocity
Since we know the momentum:
p = 6000 kg m/s
We can re-arrange the equation to find the mass of Malcom:
