A class has 11 boys, 9 girls. Two students will be selected at random to serve on committee. What's probability that both will be girls?

Given that the number of boys and girls in a class is as
follows:

Number of boys = 11

Number of
girls = 9

Then we conclude that the total number of students in the
class= 20 students.

Then, the probability of choosing a girl =
number of girls. total number of students in the class = 9/20

The
probability of choosing the 2nd girl = number of remaining girls / number of all students minus
the chosen girl = 8/19

Then , the probability of choosing two girls
is :

The probability of choosing 2 girls = 9/20 *  8
/19

                                                 =
72/380

                                                 =
18/ 95

Then the
probability of choosing 2 girls =
18/95