Answer:
speed is
meter per second and direction is
degrees
Step-by-step explanation:
As per the conservation of momentum theory, Initial momentum is equal to final momentum
![Pi_(1200) + Pi_(1500) + Pi_(2100) = Pf_(1200) + Pf_(1500) + Pf_(2100) \\m_(1200) * v_(1200) + m_(1500) * v_(1500) + m_(2100) * v_(2100) = [ m_(1200) + m_(1500) + m_(2100)] * V_f](https://img.qammunity.org/2021/formulas/physics/college/c7m4cwmmrwszb6o05hqcsmovvq5z5skk91.png)
Substituting the given values we get
Velocity in horizontal direction

Velocity in vertical direction

Final velocity

Direction of the velocity

So speed is
meter per second and direction is
degrees