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# There are 2 red and 3 blue balls in a bag. If a person takes

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Intern
Joined: 31 Jul 2003
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There are 2 red and 3 blue balls in a bag. If a person takes [#permalink]

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07 Dec 2003, 22:29
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

There are 2 red and 3 blue balls in a bag. If a person takes out 2 balls at random, what is the probability that at least one of the balls is red?
Director
Joined: 28 Oct 2003
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07 Dec 2003, 22:33
Prob that 1st ball is blue: 3/5
Prob that (if 1st ball is blue) 2nd ball is blue: 2/4
Prob of 2 blues, 6/20.

14/20
SVP
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05 Jan 2004, 17:55
I believe the probability will change if he picks two balls simultaneously and one by one.
If he picks one by one then probability is 7/10
if he picks up simultaneously then 1-3/5 = 2/5

Can you folks clarify this.
Director
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06 Jan 2004, 18:02
Quote:
believe the probability will change if he picks two balls simultaneously and one by one.
If he picks one by one then probability is 7/10
if he picks up simultaneously then 1-3/5 = 2/5

Can you folks clarify this.

No idea why that would matter...
SVP
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06 Jan 2004, 21:53
What crazy stuff I posted. I take it back. It does not make any sense at all. It really doesnt matter whether the balls are pickedup at random in one shot or pickedup one by one. The case differs however if the first ball is put back.
Sorry folks.
CEO
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07 Jan 2004, 04:10
rc197906 wrote:
There are 2 red and 3 blue balls in a bag. If a person takes out 2 balls at random, what is the probability that at least one of the balls is red?

P( none is red) = 3C2/5C2 = 3/10

P(atleast one is red) = 1 - 3/10 = 7/10
Re: Probability   [#permalink] 07 Jan 2004, 04:10
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