SOLUTION: Of a class of 25 students, 18 have brown eyes. If 2 students are chosen at random, what is the probability that both students have brown eyes.

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Question 254698: Of a class of 25 students, 18 have brown eyes. If 2 students are chosen at random, what is the probability that both students have brown eyes.
Found 3 solutions by edjones, drk, solver91311:
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
nCr=n!/((n-r)!r!) Combination of things r at a time.
.
18C2/25C2
=153/300
=.51
.
Ed

Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
The probability is
18c2*(7c0) / 25c2 = 0.51
We include the 7c0 to represent the 7 kids not with brown eyes and we want 0 of them.

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!





You can do your own arithmetic.

John