# Which card (s) must you turn over to verify if the rule has been followed?

• Only A
44%(4)50%(7)Vote60%(3)
• A & 3
44%(4)36%(5)Vote20%(1)
• A & 7
12%(1)7%(1)Vote0%(0)
• A & K
0%(0)0%(0)Vote0%(0)
• K & 3
0%(0)0%(0)Vote0%(0)
• K & 7
0%(0)7%(1)Vote20%(1)
• Only 3
0%(0)0%(0)Vote0%(0)
Select a gender to cast your vote:
I'm a GirlI'm a Guy

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## Most Helpful Girl

• I voted C last night. I'm not that disappointed that people voted B. But voting A is very disappointing.

let's just open it then. you know it I guess.
There is one example needed to prove this statement false.

First, because I saw most people voted "only A", I should say you have to check 2 cards or more, not one. It's the easier part that you should understand on sight if you are any good at analytic thinking. because if you turn over A and find 3 behind it, or if you turn it over and don't find 3 behind it, if you accept the statement or if you consider it false based on that, it's an argument from ignorance and a conclusion based on lack of contrary evidence. You have to check at least 2 cards or all the possible options if there were more, unless all other 3 cards except "A" didn't fit in the statement. So it's something between B, C, D, and F. the poll is disappointing.

But why is C true and B is false? because someone maybe come and say the statement was "if one side says A then the other side is 3" (always), the statement wasn't "if one side says 3 then the other side is always A". So checking 3 to find out if the statement is false or true is irrelevant, even if behind "3" was "A". And if behind A is 3, and behind 3 is A, it only confirms the statement, still leaving 1 card that can disprove the statement which is "7". there aren't 2 remaining cards that can disprove the statement because "K" is not in the statement and doesn't matter what is behind it, but "7" might be a part of the statement. "K" and "3" are irrelevant because they simply can't make the combination of "if x then y" in the statement. whatever is behind k doesn't matter, whatever is behind 3 doesn't necessarily prove or disprove the statement.

So if you check A and find out the statement is true or false, it doesn't yet fully prove or disprove anything, and if you check 3 after it to escape the lack of contrary evidence, it still doesn't prove or disprove anything.

So you check A, then 7. two cards that actually can disprove the statement. All "A" to see if there's "3" behind them, all numbers that aren't "3" to check if behind them is "A". Then you draw your conclusion.

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• This video uses slightly different numbers/letters but I think it explains it clearly...