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# 9, 99 or 999?

## Question

I am thinking about one number, it's 9, 99 or 999. You can ask one question to me on which I can answer yes or no to find out what number I'm thinking of. What question do you have to ask?

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Are you a number greater than 9 and less than 999?

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But If the number would be 9 or 999, the answer to your question would be 'no'. So you would only find out if the number is 99

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Question: Do you write the number with a comma?

Edited by emmybean
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There are no comma's in the numbers themselves

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How many digits are there in the number?

or

What number are you thinking of?

or

What would you get if you multiply it by 1

or

What would you get if you add one/sutractone/divide by one, etc.

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Will your response contain the same number of letters as the number's digits?

yes - 999
no - 9
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if you deduct 7, will the remainder be a prime number?

Edited by razmanugget
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Will your response contain the same number of letters as the number's digits?

yes - 999

no - 9

But as phrased, if the number were 999 a response of either 'yes' or 'no' is equally valid. However, clearly, we need a question that can give 3 different types of responses, a yes, a no, or a lack of response...

I would ask: what answer has as many letters as digits in the number you are thinking of? If "Yes" the number is 999, if "No" it is 99; silence implies it is 9.

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THis cannot be possible, if there are 2 responses you can at most reduce it down to 2 of the 3 possible answers.

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THis cannot be possible, if there are 2 responses you can at most reduce it down to 2 of the 3 possible answers.

What about impossible to respond? That is the third possibility.

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1st of all, we must understand that we need to ask him questions that could contain only yes or no as answers, not questions like 'What number are you thinking of?' See if this solution is logically correct..

Write down the numbers 9, 99 and 999 in 3 different pieces of paper.. Beneath the no 9, write down the question "Is 1<2?" Beneath the no 99, write down "Is 1>2?" Beneath 999, write down any question for which the person cannot answer a yes or a no with confidence, such as "Will South Africa win the next cricket World Cup?"

Now showing these 3 pieces of paper, ask the person, "Is the answer to the question beneath the number in your mind 'yes'?"

Interpretation of his answers: Yes-9; No-99; Dont know/Cant say-999..

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Is 90 / (your_number - 9) = 1?

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Will your response contain the same number of letters as the number's digits?

yes - 999

no - 9

But as phrased, if the number were 999 a response of either 'yes' or 'no' is equally valid. However, clearly, we need a question that can give 3 different types of responses, a yes, a no, or a lack of response...

I would ask: what answer has as many letters as digits in the number you are thinking of? If "Yes" the number is 999, if "No" it is 99; silence implies it is 9.

Could you provide a truthful response which contains the same number of letters as the number's digits?

yes - 999

no - 9

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Will your response contain the same number of letters as the number's digits?

yes - 999

no - 9

But as phrased, if the number were 999 a response of either 'yes' or 'no' is equally valid. However, clearly, we need a question that can give 3 different types of responses, a yes, a no, or a lack of response...

I would ask: what answer has as many letters as digits in the number you are thinking of? If "Yes" the number is 999, if "No" it is 99; silence implies it is 9.

Could you provide a truthful response which contains the same number of letters as the number's digits?

yes - 999

no - 9

If he says "Yes", the number might be either 999 or 99, because the truthful response he

could have provided might have been either "Yes" or "No".
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Will your response contain the same number of letters as the number's digits?

yes - 999

no - 9

But as phrased, if the number were 999 a response of either 'yes' or 'no' is equally valid. However, clearly, we need a question that can give 3 different types of responses, a yes, a no, or a lack of response...

I would ask: what answer has as many letters as digits in the number you are thinking of? If "Yes" the number is 999, if "No" it is 99; silence implies it is 9.

Could you provide a truthful response which contains the same number of letters as the number's digits?

yes - 999

no - 9

If he says "Yes", the number might be either 999 or 99, because the truthful response he

could have provided might have been either "Yes" or "No".

(for 99) He couldn't provide any response as they (1) wouldn't be truthful or (2) wouldn't contain an equitable number of letters to digits.

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(for 99) He couldn't provide any response as they (1) wouldn't be truthful or (2) wouldn't contain an equitable number of letters to digits.

If my number is 99, and you ask whether I could provide an answer with as many letters as digits in my number, my truthful response would be "Yes" because I

could provide such an answer (the fact that said answer is actually "No" doesn't matter).
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first you have to subtract 7 from 999 and you get 992 but what i did is i divided 999/7 and got 142 with a remainder of 5 and then i multiplyed it then added 5 and got 999.

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first you have to subtract 7 from 999 and you get 992 but what i did is i divided 999/7 and got 142 with a remainder of 5 and then i multiplyed it then added 5 and got 999.

Hi w10, and welcome to the Den.

Hope you enjoy solving puzzles here and posting some of your own.

You have a certain "outside the box" approach to solving them.

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