Question

Mr. Parietti needs two students to help him with a science demonstration for his class of 18 girls and 12 boys. He randomly chooses one student who comes to the front of the room. He then chooses a second student from those still seated. What is the probability that both students chosen are girls? Enter your answer as a fraction in the form a/b (for example 2/3, 5/7) or as an integer.

Answer 1

Answer:
51/145
Explanation:
Starting off, there are 18 girls, and for the first part of this question you are attempting to find the probability of the chance of randomly selecting a girl. Because the total amount of students is 30, your first fraction is 18/30. After that, you now need to find the probability that the teacher picks another girl. Since one girl has already been picked, the denominator becomes 29, and the numerator becomes 17, because there is one less student in the group overall and there is one less girl in the group. Then, you multiply 18/30 by 17/29 and you get 306/870. Divide both by 6, and you get 51/145.