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![[Post New]](/templates/default/images/icon_minipost_new.gif) 11 Mar 2007 17:32:24 IST
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A person draws two card successively without replacement from a pack of cards . He tells that both cards are aces, what is the probability that both the card are aces, if thr are 60% chances that he speaks thr truth??? whats the answer???? m getting 3/379... nd the answer given is 3/443
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Manasi....
NIT-Allahabad...
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Challenges are High, Dreams r New..
The World out thr is waiting for U !!
Dare to dream, Dare to Try..
No Goal is distant, no Star is too high !!! |
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11 Mar 2007 18:07:49 IST
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hey...
d ans. is 3/443....
wen he says a lie, take no. of ways as [52]C[2] - [4]C[2].....
as dere r cases wen one of cards is an ace n d other is not...
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12 Mar 2007 11:37:06 IST
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post the solution plsss
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Manasi....
NIT-Allahabad...
............................................................
Challenges are High, Dreams r New..
The World out thr is waiting for U !!
Dare to dream, Dare to Try..
No Goal is distant, no Star is too high !!! |
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Prats is correct Mansi.... you have not considered the cases when only one of the two cards is ace, this case will come under the condition when he tells a lie...
So, we get the probability as
(3/5)4C2 / [ (3/5) ( 4C2) + (2/5) (52C2 - 4 C 2)]
Which, on solving, gives 3/443
What you have done is that you have considered unfavourable cases as 48C2, and hence those cases in which one of the cards is ace but the other is not, have been ignored... need ny more explanation???
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Sudeep Kumar
(B tech, IITd)
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14 Mar 2007 19:36:39 IST
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another silly mistake  thanx for solving..... nopes no more doubt....
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Manasi....
NIT-Allahabad...
............................................................
Challenges are High, Dreams r New..
The World out thr is waiting for U !!
Dare to dream, Dare to Try..
No Goal is distant, no Star is too high !!! |
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