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**anna_gg****Member**- Registered: 2012-01-10
- Posts: 232

Use number 8 6 times to make 1000.

You can only use +, -, *, /, square root and parenthesis ().

No factorials, 3rd root or any other numbers.

Thank you!!!

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi anna_gg;

Welcome to the forum! Do you know whether this has an answer or not?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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**anna_gg****Member**- Registered: 2012-01-10
- Posts: 232

It does, but I don't know it! All my attempts end up in using 7 8's or more!

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Yes, there are lots of solutions for 8 8's and perhaps for 7 8's also. But I have never seen one for 6 8's.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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**bob bundy****Administrator**- Registered: 2010-06-20
- Posts: 8,228

hi anna_gg and bobbym

I've got some 7 eights solutions. But 6 is still eluding me.

Bob

The five weighings problem is getting very complicated.

I'm doing things like balance 2 unknowns against 1.

If they balance then they must be (10,20,30) or (10,30,40) or (10, 40,50) or (20,30,50)

If the two go down then (10,20,40) or (10,20,50) or (10,30,50)

If not then there's loads of possibilities eeekkk.

Depending on which, try other balance possibilities.

The total map of alternatives is very large!

OR

(Im)Balance any pair and call them v and w so that v<w

(Im)Balance another pair and call them x and y so that x < y.

Then try w against x. Again lots of possibilities.

Cannot find a simple, elegant way to tackle this.

*Last edited by bob bundy (2012-01-11 03:12:06)*

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**bob bundy****Administrator**- Registered: 2010-06-20
- Posts: 8,228

hi anna_gg

Bob

*Last edited by bob bundy (2012-01-11 07:11:21)*

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**anna_gg****Member**- Registered: 2012-01-10
- Posts: 232

We are only allowed to use decimals in the form 8.8, not .8, as this assumes leading zeros

Otherwise, another like that would be 888/.888.

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**bob bundy****Administrator**- Registered: 2010-06-20
- Posts: 8,228

hi anna_gg

Please would you post the exact wording in the original question.

I'm 'clutching at straws' now.

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

I have done a large computer search for some answer, also a search of the available literature for these type problems. I am coming up dry.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

Are exponents allowed? I thought they were not.

Hi Benice;

If they are then nice solution!

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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**anna_gg****Member**- Registered: 2012-01-10
- Posts: 232

Awesome! Thanks!!!

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**bob bundy****Administrator**- Registered: 2010-06-20
- Posts: 8,228

It is a nice solution.

But I thought you weren't allowing powers.

That's why I asked for the exact wording.

So is this question done now?

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**anna_gg****Member**- Registered: 2012-01-10
- Posts: 232

Not sure about powers; I must confirm this with the friend who gave me the problem.

Either way, I could not go that close myself!

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi anna_gg;

If it does not include powers can you have your friend clearly state what is good and what is not?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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**anna_gg****Member**- Registered: 2012-01-10
- Posts: 232

Confirmed that powers are allowed!

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

Then I guess this question is closed unless you want more of them.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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**anna_gg****Member**- Registered: 2012-01-10
- Posts: 232

Thank you all for your help!!

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