SOLUTION: In a sample of 600 students, 150 are seniors. If two students are selected at random from the sample, find the probability both students are seniors.

Question 474485: In a sample of 600 students, 150 are seniors. If two students are selected at random from the sample, find the probability both students are seniors.

Answer by htmentor(1343) (Show Source): You can put this solution on YOUR website!
In a sample of 600 students, 150 are seniors. If two students are selected at random from the sample, find the probability both students are seniors.
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The probability that the 1st is a senior is P(1st) = 150/600
Once the first is selected, there is one fewer student and one fewer senior.
So the probability that the 2nd is a senior is P(2nd) = 149/599
The probability that both are seniors is the product of these:
P(both) = P(1st)P(2nd) = 150/600*149/599 = 1/4*149/599 = 0.0622
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