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## #1 2005-08-26 07:38:27

stef
Novice

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### Looking for the fifth number

Hi,

for a science quiz I got the following question. Which numbers should be filled in at ...?
137 153 163 127 ...
So obviously we are looking for a number with three digits.
I know the first digit is not 1 (that is why this is not easy I guess) and the second digit is not 7 or 8. My best guess is taking the middle number as the mean and then ... is 235. But this may be far-fetched? who has a better idea?

thanks thanks thanks. Stef;

PS: don't know whether I should view this as a series or as something else?

## #2 2005-08-26 08:29:39

kylekatarn
Power Member

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### Re: Looking for the fifth number

for me, the most funny aspect of these type of problems is that we can approach the given values mathematically or logically. and both answers are correct!

## #3 2005-08-26 09:23:04

mikau
Super Member

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### Re: Looking for the fifth number

not sure I understand the question. Is this an Arithmatic Mean type problem?

A logarithm is just a misspelled algorithm.

## #4 2005-08-26 09:47:51

MathsIsFun

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### Re: Looking for the fifth number

Mathematically you could find lots of things to fit that. A polynomial for example. But it was a Science Quiz, so I expect you are supposed to recognize something.

And how did you know it as a) three digits, b) first digit is not 1, and c) second digit is not 7 or 8 ??

Could we have all the information surrounding it,  please?

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

## #5 2005-08-26 17:12:20

stef
Novice

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### Re: Looking for the fifth number

Thanks to all for your replies. Here is some more information.

Ultimately what I need to do is solve a Sudoku puzzle. However, at start, the sudoku is empty so I need to find numbers to fill in the Sudoku in part and then solve it by logic (as you always would solve a Sudoku). So I am trying to find numbers. Most of them I have already found since the answers to the other questions are more science related. For some answers I am quite sure. That is why I know for instance that on position 2 (the second digit) of my ... (unknown number) it can never be a 7 or 8 since that would put my Sudoku in error (i.e. two times an eight in the same row or two times a 7 in the same box). For the first digit, it can hardly be a one, since this would again contradict with a previous answer of which I am 98 % sure. Oh by the way, I am sure I am looking for a number with 3 digits since the question is prased to find 137 153 163 127... (so three dots) but in addition I know the answer gives me three digits for my Sudoku. I agree that in any case many answers should be possible but with the restrictions above, maybe only one true answer is possible. So I am looking for logical OR mathematical solutions to my problem. Hope this helps. Thanks for your brains. Stef.

## #6 2005-08-30 06:43:40

John E. Franklin
Guest

### Re: Looking for the fifth number

Who knows, but I guess 117, so it goes 137 153 163 127 117 173 183 107 97 193 203 87 77...