Well, st first we should find initial momentum for the first person represented in the task which definitely must be :
\((65+0.045)*2.5\)
And then we find the final one : \(65*x + 0.045*30\)
Then equate them together : \(x=2.48 m/s\)
So we can get the velocity, which is \(is 2.48 m/s\)
In that way, according to the main rules of conservation of momentum you can easily find the solution for the second person.
Regards!
