Answer:
7/18
Explanation:
P(sophomore girl) is 7 out of a total 30.
P(girl) is 18 out of 30.
(7/30) / (18/30) = 7/18
If you just look at the girls column you can see this immediately. A given is that we're looking for a girl (18 girls), then what is the chance that it's a sophomore. That is 7 out of 18.