ef1
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Post by ef1 on Jan 3, 2007 11:43:07 GMT
"every card marked on one side with 'a' will have a '3' on the other side."
this statement might be true or false.
if there are four cards on the table showing '3','a','d','7',
whats the least number of cards that you have to turn over to proove if the first statement is true or false?
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zetan
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Post by zetan on Jan 3, 2007 15:22:25 GMT
2? Because you'd have to prove each card - the card with the three should have an A on the other side... and vice-versa with card with the A...  I'm probably wrong. |
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dotajames
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Post by dotajames on Jan 3, 2007 17:39:16 GMT
Hmm I think it's actually 3. At first I thought it was one (just the 'a' card, because if the '3' card has something different on the other side that doesn't disprove the statement). Then I realised that if the 'd' and '7' cards had an 'a' on the other side the statement would be false. So I say three cards.
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zetan
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Post by zetan on Jan 3, 2007 22:03:40 GMT
yes... you're right!
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ef1
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Post by ef1 on Jan 4, 2007 10:17:23 GMT
the answer is 2. the a and the 7. not the d because that will have a number on the other side.
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