Answer:
[tex]v_f=8.4m/s[/tex]
Explanation:
We need to use the conservation of momentum Law, the total momentum is the same before and after the kid leaves the skate.
In the axis X:
[tex](m_{kid}+m_{skate})*v_{o}=m_{kid}*v_f[/tex] (1)
[tex]v_f=(m_{kid}+m_{skate})*v_{o}/m_{kid}=(44+2.2)*8/44=8.4m/s[/tex]