Two asteroids strike head-on: before the collision, asteroid A (mA = 7.5 1012 kg) has velocity

Question:

Two asteroids strike head-on: before the collision, asteroid A (mA = 7.5 × 1012 kg) has velocity 3.3 km/s and asteroid B (mA = 7.5 × 1012 kg) has velocity 1.4 km/s in the opposite direction. If the asteroids stick together, what is the velocity (magnitude and direction) of the new asteroid after the collision?