1. The problem statement, all variables and given/known data In a certain frame S, two events A and B are separated spatially by 3ly with A occuring 1 year before B. What must be the relative speed of a frame S' such that the two events occur simultaneously? 2. Relevant equations 3. The attempt at a solution Don't I just use: dt' = gamma(dt-B/c dx) but when i put in dt = 1 and dx = 3 i get to gamma = 3B/c which i can't solve! am i doing it right?