Alright so from my understanding of what you said the three events in the unprimed frame are, (x,t)
and the gamma that should be used is the one where racerone's velocity is used or
and then the transforms can be calculated for...
Two racers start in between two finish lines of equal distance 'd' , ie a distance 2d sits between the two lines with the racers sitting a distance d from each. Refferees who time the race in the earth frame are able to say that both racers start at time=0s and at the same...