# Consider a two-way table that summarizes age and ice cream preference. Of the children, 7 prefer vanilla, 12 prefer chocolate, and 3 prefer butter pecan. Of the adults, 10 prefer vanilla, 31 prefer chocolate, and 8 prefer butter pecan. What is the conditional probability that a person prefers vanilla, GIVEN THAT the person is an adult?

$\frac{10}{49}$
in total there are $10 + 31 + 8$ adults, which is $49$ adults.
of the $49$ adults, $10$ prefer vanilla.
$\frac{10}{49}$ of the adults prefer vanilla. hence, the probability of choosing someone who prefers vanilla out of the adults is $\frac{10}{49}$.