Answer:
0.4929 = 49.29% probability that he voted in favor of Scott Walker
Step-by-step explanation:
Bayes Theorem:
Two events, A and B.
In which P(B|A) is the probability of B happening when A has happened and P(A|B) is the probability of A happening when B has happened.
In this question:
Event A: Having a college degree.
Event B: Voting for Scott Walker.
They found that 57% of the respondents voted in favor of Scott Walker.
This means that 
Additionally, they estimated that of those who did vote in favor for Scott Walker, 33% had a college degree
This means that 
Probability of having a college degree.
33% of those who voted for Scott Walker(57%).
45% of those who voted against Scott Walker(100 - 57 = 43%). So

What is the probability that he voted in favor of Scott Walker?
0.4929 = 49.29% probability that he voted in favor of Scott Walker