Car 1 is travelling at 3/4c. Car 2 in behind Car 1 is travelling at 1/2c. Car2 fires a bullet that travels at 1/3 c. OK. In order to determine whether the bullet reaches Car 1 or not we need to use Einsteins velocity addition rule and determine whether the relative velocity of the bullet with respect to Car 1 is positive or negative, correct? Is it safe in special relativity to say that the velocity of Car 2 with respect to Car 1 is 1/2c - 3/4c? Or do I need to do another velocity addition rule to calculate that?