Probability question ?

9 boys and 12 girls on a trip. There’s 6 students that will be selected to go. What is the probability that only girls will be on the trip. Round to the nearest thousandth. 

?2021-03-25T00:35:21Z

There are thus 21 students to choose from.

There is a prob of 12/21 for the first chosen be a Girl. 
Then, there is a prob of 11/20 for the next chosen be a Girl.
Then, there is a prob of...

See the pattern? Six times. 

The sought prob is the multiplication of these six probs.

Final answer = ?

Done!