Rachel and Robert run on a circular track. Rachel runs counterclockwise and completes a lap every 75 seconds, and Robert runs clockwise and completes a lap every 60 seconds. Both start from the same line at the same time. At some random time between 10 minutes and 11 minutes after they begin to run, a photographer standing inside the track takes a picture that shows one-fifth of the track, centered on the starting line. What is the probability that both Rachel and Robert are in the picture?
