card game

Charlie has 7 cards numbered 1, 2, 3, 4, 5, 6 and 7 and randomly deals 3 of them to Alice and 3 to Bob. All three people look at the cards that they hold. Can Alice and Bob communicate with each other, in the presence of Charlie, so that after the communication Alice knows which cards Bob has, and Bob knows which cards Alice has, but, for any card except the one he has, Charlie does not know whether Alice or Bob has it?

15 Answers

1
Unicorn--- Extinct!! ·

Yeah...Yeah!!!!

"Aakhon hi aakhon mein ishara ho gaya!!" [4]

1
Arshad ~Died~ ·

dat is not the answer....he he....
[194]

1
Arshad ~Died~ ·

anyone???

1
Unicorn--- Extinct!! ·

Kaha to!!! "Aakhon hi aakhon mein...."

1
Kaustab Sarkar ·

ishara ho gaya"" [3][3][3][3][3][3][3][3][3][3]

1
Arshad ~Died~ ·

ohk yaar try telling someone u have a seven with ur eyes...
[299]
ps-wat if u are wearing sunglasses

1
Kaustab Sarkar ·

is this ur doubt[3] or challenge[3] [247]

1
Arshad ~Died~ ·

take it as a question....
if a question is made it can be solved....
why get interested only if its a challenge....

49
Subhomoy Bakshi ·

hi but what is the answer???????????

1
Arshad ~Died~ ·

no one yet????

49
Subhomoy Bakshi ·

well mai hota toh...i wd hav snatched the card 4m charlie n showed it 2 the other one......yeh hoga kya???????

1
Arshad ~Died~ ·

nahiiiiiiiiiiiiiiiiiiiii...........................keep some standard dude...!!!

1
bagla93 ·

It's simple dude......
Bob and Alice can show to each other the cards they have.....

Most probably all three would be sitting in a triangular arrangement and one end would be free where Charlie would not be there.

21
omkar ·

Yes. Alice and Bob both announce the sum, mod 7, of their cards. Charlie's card is the negative of the sum of Alice's and Bob's total, mod 7. The only information Alice and Bob have given Charlie is what Charlie already knows: his own card. From this, both Alice and Bob can deduce each other's cards.

39
Pritish Chakraborty ·

sibal copied it from here : http://2000clicks.com/MathHelp/PuzzleTPS200802CardTrickAnswer.aspx

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