Brain Teasers
Honest, Hey?
My name is Grungy. I am an honest person, and I am thinking of one of these numbers: 1, 2, or 3. You may ask me only one yes-no question - I will answer truthfully, and if you choose the right question, you will know which number I am thinking of! If I cannot answer your question, I will simply tell you that I cannot answer it.
So, what question do you need to ask me to determine what number I am thinking of?
So, what question do you need to ask me to determine what number I am thinking of?
Answer
"I am thinking of either 1.5 or 2.5 - is your number greater than mine?"If I answer, "yes", then you know it has to be 3 - because I can't tell if you're thinking of 2.5 or 1.5. If I answer, "no", it has to be 1. If I answer, "I cannot answer that question", then it is two!
If you can think of another answer, good on ya! Feel free to correct this teaser with the new answer. 8-)
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OK.........
You can do it with any decimal between 1.000...1 and 1.999... and 2.000...1 and 2.999....
Good one
You got me!
Good one.
Good one.
Awesamo!
You could ask the person if the number they are thinking of is odd. Right?
nevermind
Sorry, Bismillah, but if 1 number is even and 2 od, then you can't determine the answer.
yes you can ask if it is odd,because if he is thinking of 1,2,or3,1and3 are odd,so the answer would be 2.
And what if he said that the number was odd? That's like the same as asking "Is the number 2"?
i went with "is 1/(2-) positive?" b/c:
1/(2-1)= 1 so would be yes
1/(2-2)= 1/0 which is undefined and therefore neither positive or negative and thus he cant answer
and lastly 1/(2-3)= -1 which would be no
1/(2-1)= 1 so would be yes
1/(2-2)= 1/0 which is undefined and therefore neither positive or negative and thus he cant answer
and lastly 1/(2-3)= -1 which would be no
twas a tib bit tricky but i got it
oh yeah didnt think about that,didnt see that,sorry
I came up with "If your number is not 2, is it 1?" If it's 1, he answers yes. If it's 3, he answers no. If it's 2, he has no answer because it fails the condition.
"Is 1/(2-x) positive?" doesn't work because the answer in 1/(2-2)= 1/0 is no. (Is it positive? No.)
"Is 1/(2-x) positive?" doesn't work because the answer in 1/(2-2)= 1/0 is no. (Is it positive? No.)
You don't need decimals, you can ask the quesion with 1 and 2
My question was, "If you think of a second number different from the 1st one, will it be higher?"
Maybe the phrasing is a bit confusing, but will that be acceptable?
Maybe the phrasing is a bit confusing, but will that be acceptable?
Nope, If he said yes, It could be 1 or 2
Totally stumped me. I started thinking about the Fibonacci sequence and patterns like that until I gave up . Great job!
Barret, the if-then conditional you gave would elicit a "yes" response if Grungy's number is two.
The easiest way to see this is to examine the contraposition. A contraposition is logically equivalent (exactly the same) as the original syllogism.
For example:
Original - If a human has no eyes, then that human is blind.
Contraposition - If a human is not blind, then that human has eyes.
Because the two are logically equivalent, you could start with the listed contraposition and get the original -- back and forth, it doesn't matter.
Grungy's question is: "If your number is not two, is it one?" So he is considering the validity of the following syllogism:
- If your number is not two, it is one.
The contraposition would be:
- If your number is not one, it is two.
From that, it should be clear that Grungy answers "yes" (the syllogism is true) if is number is, in fact, two.
The confusion arises because syllogims are not normally asked when the particulars (antecedent and consequence) are both already known. Imagine that we're discussing your friend, Fred, and we both know he is a human. Now I ask, "If Fred has no eyes, then is Fred blind?"
Because he is human, the above self-evident syllogism (regarding eyes & blindness) is true of Fred. Therefore, the correct answer to the question is "yes." Being informative, you would probably ignore my syllogism and say "Fred isn't blind", but Grungy is not so helpful!
Cheers.
The easiest way to see this is to examine the contraposition. A contraposition is logically equivalent (exactly the same) as the original syllogism.
For example:
Original - If a human has no eyes, then that human is blind.
Contraposition - If a human is not blind, then that human has eyes.
Because the two are logically equivalent, you could start with the listed contraposition and get the original -- back and forth, it doesn't matter.
Grungy's question is: "If your number is not two, is it one?" So he is considering the validity of the following syllogism:
- If your number is not two, it is one.
The contraposition would be:
- If your number is not one, it is two.
From that, it should be clear that Grungy answers "yes" (the syllogism is true) if is number is, in fact, two.
The confusion arises because syllogims are not normally asked when the particulars (antecedent and consequence) are both already known. Imagine that we're discussing your friend, Fred, and we both know he is a human. Now I ask, "If Fred has no eyes, then is Fred blind?"
Because he is human, the above self-evident syllogism (regarding eyes & blindness) is true of Fred. Therefore, the correct answer to the question is "yes." Being informative, you would probably ignore my syllogism and say "Fred isn't blind", but Grungy is not so helpful!
Cheers.
Here is the different answer. If you are thinking about even digit it has to be 2 or if you are thinking about odd digit it has to be 3. Are you?
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