Puzzle survey to confirm a published result

[CraigD]

According to a recent book I read, the following puzzle, though relatively simple and completely uncontroversial, will be answered incorrectly by more than 80% or respondents:

 

Each card has a single letter on one side, a single number on the other. (As is normal with cards) you can only see one side of each card. You see these 4 cards:

 

A F 2 7

 

You are asked to determine the truth of the statement “every card with a vowel on one side has an even number on the other” by flipping as few cards as possible.

 

Which cards should you flip?

 

I would like to test the claim that fewer than 20% of respondents answer correctly, so:

• Please don’t view the poll results before voting
  
• Please take as much time as you would like to arrive at an answer, then vote above.
  
• Feel free to use paper and pencil, or a computer, but please do not search the internet or any other reference.
  
• Please do not comment – after 30 votes have been collected or a couple of days passed, I’ll post the correct response

PS: There should be 16 possible answers, but the poll feature limited me to 10. :confused:

 

The results of the poll, and the correct puzzle answer, are at 4723

Please do not vote after visiting the results thread. You will taint the poll. Clay

[Edge]

Can we comment on this?

[C1ay]

Can we comment on this?

Did you read post #1?

Please do not comment – after 30 votes have been collected or a couple of days passed, I’ll post the correct response

[CraigD]

Can we comment on this?

Please feel free to PM me if you have any questions about the riddle. The survey places no restriction on the amount of clarification that can be given, only that you give your answer without any biasing influences. Someone seeing the answers to another person’s questions in the public forum could be biasing.

 

I’m hoping to get at least 30 votes before ending the survey – after 22 hours, we have 10 – but will give up by Friday if we can’t reach that count.

[C1ay]

I’m hoping to get at least 30 votes before ending the survey – after 22 hours, we have 10 – but will give up by Friday if we can’t reach that count.

Why give up? I propose that we start a thread elsewhere, math forum?, to discuss it after the 30 votes and let the poll keep running. I can delete the comments that exist and we can bump the thread as needed to get more votes.

[Chacmool]

Why give up? I propose that we start a thread elsewhere, math forum?, to discuss it after the 30 votes and let the poll keep running. I can delete the comments that exist and we can bump the thread as needed to get more votes.

I second that. I'm amazed by the answers already given, and I'm very curious to see the result.

[Tormod]

Yeah this a good example of a simple science experiment. :confused:

 

Come on everyone, cast your vote!

[Dark Mind]

I already did :).

[CraigD]

The results of the poll, and the correct puzzle answer, are at 4723

[Dark Mind]

Hooray! Got it right :cup:.