The body is at rest and force is internal hence the body breaks due to equal force so,
when mass=200 g=0.2 kg
and velocity=12 m/s
Force=mass*velocity=0.2 kg*12 g=2.4 N
equal force on the other part so,
velocity=2.4 N/0.3 kg=8 m/s.
the other part will move in the opposite direction that is south.