Help solving

A 69.0-kg astronaut is in space, far from any objects that would exert a significant gravitational force on him. He would like to move toward his spaceship, but his jet pack is not functioning. He throws a 0.720-kg socket wrench with a velocity of 5.00 m/s in a direction away from the ship. After 0.500 s, he throws a 0.800-kg spanner in the same direction with a speed of 8.00 m/s. After another 9.90 s, he throws a mallet with a speed of 6.00 m/s in the same direction. The mallet has a mass of 1.20 kg. How fast is the astronaut moving after he throws the mallet?(assume all speeds are relative to the spaceship). m/s ok