Let the event that the students were under 25 be A and the event that the student got a "B" be B.
[tex]P(A\cup B)=P(A)+P(B)-P(A\cap B)[/tex]Using the tables, we can find that:
[tex]\begin{gathered} P(A)=\frac{43}{75} \\ P(B)=\frac{35}{75} \\ P(A\cap B)=\frac{19}{75} \end{gathered}[/tex]Therefore,
[tex]P(A\cup B)=\frac{43}{75}+\frac{35}{75}-\frac{19}{75}=\frac{43+35-19}{75}[/tex]Thus,
[tex]P(A\cup B)=\frac{59}{75}[/tex]Therefore, the probability that the student was under 25 OR got an "B" is 59/75.
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