Answer:
3/4
Step-by-step explanation:
probability of any event = 
3 freshmen + 3 sophomores + 3 juniors + 3 seniors = 12 participants
∴the total number of participants = 12
P(freshman is a captain) = 
=
=
P (freshman is not a captain) = 1 - 
= 
whenever the probability of an event not happening is being calculated, always subtract the possibility of the occurrence of such event from 1
If you expand the left hand sign, the equation becomes

This means that the term
cancels out, since it appears in both sides. So, we're left with

which is clearly false, i.e. it leads to an impossible equation, which thus have no solutions.
Can you show a better photo some of the question is cut off
It’s the third one. Hopefully this helped