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There is a letter on one side of each card and a number on the other side. Which card(s) must you turn over to determine whether the following statement is false? "If a card has a vowel on one side, then it has an even number on the other side." _____________________________________________________________________ Options (1) and (2) (1) Has a 80% chance of proving the statement false. A + even number = cannot determine A + odd number = statement false (2) Has a 20% chance of proving the statement false 7 + vowel = statement false 7 + consonant = cannot determine Unless you are a mindreader you MUST choose "A" first in your effort to prove that the statement in question is false. So the answer is "A", and that's that. 
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Quote:
There is a letter on one side of each card and a number on the other side. Which card(s) must you turn over to determine whether the following statement is false?
"If a card has a vowel on one side, then it has an even number on the other side."
_____________________________________________________________________
Options (1) and (2)
(1) Has a 80% chance of proving the statement false.
A + even number = cannot determine
A + odd number = statement false
(2) Has a 20% chance of proving the statement false
7 + vowel = statement false
7 + consonant = cannot determine
Unless you are a mindreader you MUST choose "A" first in your effort to prove that the statement in question is false.
So the answer is "A", and that's that.
Careful there Milo, Thanksgiving is coming up. Someone might mistake you for a Thanksgiving Turkey instead of a Christmas one.
You've had it explained to you several times so I won't bother doing it again.
Meanwhile, behind door two is a bag of used dog food. Wanna change your mind about which door you choose?
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"You've had it explained to you several times so I won't bother doing it again." said Faldage.
__________________________________________________________________
Aw shoot, you got me there, Faldage, and I promise I won't bother you by asking you to explain it to me again. But one thing...
What part of 80% consonants and 20% vowels (not counting the "Y") is it that you don't understand?
Take your time...
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there you go again. there are exactly four(4) cards in evidence, no more.. no less -- of these there is one vowel, one consonant, one even number, one odd number on display.
you (re)do the math.
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Oh nooooooo! Not you too, Joe Friday? This is terrible.
Worse than being wrong is being the only one who is right.
Can any swinging chick or Dick, Tom or Harry, in this building help me out?
Look, this ain't rocket science, it's probability theory. "Basic" probability theory. Just enough to keep your own shirt for five minutes in a fast game of Mississippi Tont.
Yes Joe, I know that there are only four cards in the hole, but I also know that the odds are four to one against turning up a vowel in the flip.
Naturally the odds are even on in turning up an odd number or even number, ad infinitum.
Now take a deep breath and apply this information to the question at hand.
Please?
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>but I also know that the odds are four to one against turning up a vowel in the flip.
this is where you've totally, irrevocably screwed the pooch. the odds of turning up a vowel "in the flip" depend completely on the (perverted?) nature of the person who selected the card in the first instance.
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Quote:
>but I also know that the odds are four to one against turning up a vowel in the flip.
this is where you've totally, irrevocably screwed the pooch. the odds of turning up a vowel "in the flip" depend completely on the (perverted?) nature of the person who selected the card in the first instance.
That's my boy, Joe, you are completely right. But since we know not of the nature of his "perversion" we must employ the "laws of probability" in order to make the best guess.
And the best guess is to choose card "A" first in order to avoid having to guess a vowel at one in four odds.
Whew, now I feel better knowing that Joe is on my side.
Last edited by themilum; 11/02/06 01:34 AM.
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So, Milo. Now that you know door two has a bag of used dog food behind it, are you or are you not going to change your pick?
Besides, the only letters shown are A and B. As far as you know they're not even Latin alphabet. Might be Greek or Cyrillic. What does that do to your "probabilities"?
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Quote:
Besides, the only letters shown are A and B.
The problem doesn't even require that there are only letters, numbers, or that there is only one thing on the back. For example, the 7 card could have a picture of some dog food, a blood stain and a star, "SEVEN", ... It could even be blank.
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calling Mr. Schroedinger.
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