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candies...

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candies...

by gmatrant » Tue Oct 28, 2008 7:48 am
If two candies are drawn at random from a jar with only red and blue candies and not
replaced there is a 70% chance of selecting at least one red. If there is a total of 5
candies in the jar, how many of them are red?
(A) 5
(B) 4
(C) 3
(D) 2
(E) 1
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Re: candies...

by logitech » Tue Oct 28, 2008 7:59 am
gmatrant wrote:If two candies are drawn at random from a jar with only red and blue candies and not
replaced there is a 70% chance of selecting at least one red. If there is a total of 5
candies in the jar, how many of them are red?
(A) 5
(B) 4
(C) 3
(D) 2
(E) 1
so there is a 30% chance of selecting NO RED! --> which means all Blue

"not replaced"

So

B/5 x (B-1)/4 = 3/10

B = 3

Therefore, R = 2

D as in DRACULA 8)
LGTCH
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