Answer:
35/132
Step-by-step explanation:
The probability of selecting a boy for president is 7/12, the ratio of the number of boys to the number of candidates. Then the probability of selecting a girl for vice president is 5/11, the ratio of the number of girls to the remaining number of candidates. The joint probability is ...
(7/12)(5/11) = 35/132 . . . P(b=P&g=VP)
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We can also look at this another way.
The number of ways two candidates can be selected from 12 is 12P2 = 132. The number of ways that the first can be a boy and the second can be a girl is (7)(5) = 35. Then the probability of a (BG) pair from the 12 candidates is 35/132.
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<em>Additional comment</em>
These numbers assume that selection is random and all possibilities are equally-likely. That is unlikely to be the case in an election.
