We have to calculate the probability that a student selected at random is a male given that it is a senior.
This probability can be written as the quotient between the probability that a student is male and senior and the probability that the student is a senior:
[tex]P(M|S)=\frac{P(M\cap S)}{P(S)}[/tex]We have 2 male and seniors, and there are 2+3=5 seniors (including male and female).
Then, being N the sample size, we can write:
[tex]P(M|S)=\frac{P(M\cap S)}{P(S)}=\frac{\frac{2}{N}}{\frac{5}{N}}=\frac{2}{5}=0.4=40\%[/tex]Answer: 40%
