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Mr. Smith's class has 7 boys and 10 girls. If two students are randomly selected, what is the probability they are both boys? After selecting the first student, he does not go back in the room before the second student is selected. Answer as a simplified fraction.​

2 Answers

3 votes

Answer:


(21)/(136)

Explanation:


(7)/(17) * (6)/(16) = (7)/(17) * (3)/(8) = (21)/(136)

User Atavio
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3 votes

Answer:

21/136

Explanation:

The probability of selecting a boy from the class on the first draw is 7 boys out of 17 students total, or 7/17.

After the first boy is selected, there will be 6 boys and 10 girls left in the class.

So the probability of selecting a boy on the second draw, given that a boy was already selected on the first draw, will be 6 boys out of 16 remaining students, or 6/16.

To find the probability that both students selected are boys, we can multiply the probabilities of selecting a boy on the first and second draws:

P(boy and then boy) = P(boy on first draw) x P(boy on second draw | boy on first draw)

P(boy and then boy) = (7/17) x (6/16)

P(boy and then boy) = 21/136

Therefore, the probability of selecting two boys from Mr. Smith's class is 21/136.

User Munomono
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8.2k points