Krish C. answered • 6d

Highly-Rated Mathematics Tutor

Initially you have 12+9=21 students

To choose the first one as a girl, you have 9 options out of 21, so the probability is 9/21

Next, to do this the second time, you have 8 girls left, out of 20 students, so 8/20

Again, we have 7 girls and 19 students, 7/19

And finally we are left with 6 girls and 18 students, so the probability of picking the last student as a girl is 6/18

To get the probability of the 1st and 2nd and 3rd and 4th student as a girl, focus on the AND

AND means multiplication, multiply the 4 probabilities and that's your answer.

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