the answer is 0.18, because if you add 11 and 9 you get 20. which means there is 20 total students in the class. the probability of choosing a girl would be 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 is 18/95 so the answer is 0.18
