Question

There are 21 girls and 33 boys in a classroom. A student is randomly selected to become the class leader. If I want to find the probability that the selected student is a girl, the number of favourable outcomes is ___.

Answer 1

I want to find the probability that a girl is selected.
$\Rightarrow$ A girl being selected is a favourable outcome.
Here, there are 21 girls. In other words, a girl can be selected in 21 ways.
$\therefore$ Number of favourable outcomes is 21.