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
= 18/ 95
Then the probability of choosing 2 girls = 18/95
check Approved by eNotes Editorial