In a class, there are 12 boys and 16 girls. One of them is called out by an enroll number, what is the probability that the one called is a girl?

Solution (By Examveda Team)

Let S be the sample space
Total number of students in the class = 12 boys + 16 girls = 28
Then, n(S) = 28
Let E be the event of calling one of them by enroll number
Given that, number of girls = 16
Then, n(E) = 16
The probability that the one called is a girl
$$\eqalign{ & = \frac{{{\text{n}}\left( {\text{S}} \right)}}{{{\text{n}}\left( {\text{E}} \right)}} \cr & = \frac{{16}}{{28}} \cr & = \frac{4}{7} \cr} $$