Good evening. I am struggling in solving this problem. A spaceship is moving in a straight line away from Earth at 0.70c, measured relative to Earth. It launches a missile that moves away from the spaceship in the forward direction at 0.50c, relative to the ship. Relative to Earth, what is the speed of this missile?

0.80c

0.95 c

0.70 c

0.89c

1.48 c

Thank you very much