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
There are 9 girls and 11 boys. You first add them together to get the total and 9 + 11 is 20. The probability that it will be girls is a 9/20
girls to class then girls-1 to class-1 multiplied gives you the chances of that happening
There are 11 boys and 9 girls. To find the probability of randomly selecting two students who are both girls.
There are 11+9 = 20 students.Two students can be randomly selected from 20 in 20C2 = 20*19/2 = 190 ways.
Since the there are 9 girls , the number of ways of selecting the girls from 9 students = 9C2 = 9*8/2 = 36.
Therefore the probability that the sected two students are grls for the committee is 36/190 = 18/95.