If 102 are boys then 250 - 102 = 148 are girls.
If 20 girls run track, then 148 - 20 = 128 girls do not run track
probability a randomly chosen student from the senior class is a girl who does not run track = (probability the student chosen is a girl) * (probability the student does not run track)
= (148/250) * (128/250) = 128/250 = 62/125
