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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Hi bobbym,

I changed my answer, sorry for the delay.

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense" - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,220

No problem at all, the old guy made yet another typo. Soon under the new regime they will be putting him to sleep, permanently. Or maybe in the coming food riots they will eat him. Either way, then he can go to the big forum in the sky. The computers are faster there and he can live out eternity computing zillions of digits in the decimal expansion of 7 / 9.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Nah, we learn more if there are typos...

We think of more ways till we are assured it's a typo!

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense" - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,220

You have a point there.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,220

S = { 1,2,3,4,5,6,7, ... 1000 }. C adds 1 to every 2nd element, 1 to every 3rd element all the way up to every nth element. If n is 250 then what is 2nd largest element in the set now.

A says) 32

B says) That is not right.

C says) Requires a computer.

D says) Not really, A is right.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Hi,

*Last edited by gAr (2011-02-03 19:06:30)*

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense" - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**Howardroark****Member**- Registered: 2010-10-10
- Posts: 382

Hi bobbym,

I come from a civilization which has given the world the number 0..

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,220

Hi all;

Answer verified. Those answers are close but they are not correct. Please give it another try.

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Hi bobbym,

Check whether my understanding of the problem is correct:

For n=5, sequence is: 1 3 4 6 6 8 7 10 10 12 11 15 13 15 17 18 17 20 19...

For n=10, sequence is: 1 3 4 6 6 9 8 11 11 13 11 16 13 16 17 19 17 22 19...

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,220

Hi;

That is not correct. Remember the first time all of them get incremented by 1.

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

But the question says "C adds 1 to every 2nd element", so why are we adding 1 to all?!

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,220

Hi;

But the question says "C adds 1 to every 2nd element"

Darn you would say that. Why must they always read the questions, I do not? Because of that now we have parity. All 3 of us have wrong answers.

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Hi,

*Last edited by gAr (2011-02-03 22:45:54)*

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,220

Hi ;

That was my answer but you have refuted it in post #212 and #213.

I have conceded that the question is as you see it. But all the answers are still currently wrong.

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Hi,

My computer says answer is 1010, I only have the program to blame!

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,220

That is close but it is clear that you were on the right track with your sequence in post #210. That sequence is correct and leads to the correct answer.

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

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**Howardroark****Member**- Registered: 2010-10-10
- Posts: 382

Hi bobbym,

*Last edited by Howardroark (2011-02-03 22:58:51)*

I come from a civilization which has given the world the number 0..

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,220

Hi Howardroark;

That is a couple off.

since you r saying that one is added to all of

That has been refuted in post #212 and #213. Simply by reading the problem correctly as you both did.

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

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**Howardroark****Member**- Registered: 2010-10-10
- Posts: 382

Hi bobbym,

I come from a civilization which has given the world the number 0..

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Hi all,

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**Howardroark****Member**- Registered: 2010-10-10
- Posts: 382

Hi all,

I think gAr is right.. i didn't try for 990.. i was a fool to try till 995

I come from a civilization which has given the world the number 0..

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**Howardroark****Member**- Registered: 2010-10-10
- Posts: 382

Hi,

I verified gAr's answer with wolfram alpha..It has totally 24 divisors

I come from a civilization which has given the world the number 0..

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,220

Alright let me show what I have and let us see if we can agree.

This is the front 10 and the back 10 of sequence after C finished with it.

Divisors of 1000 are:

So 1000 gets incremented 13 times = 1013 = maximum.

Divisors of 990:

So 990 gets incrememnted 20 times = 1010 = 2nd largest.

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

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**gAr****Member**- Registered: 2011-01-09
- Posts: 3,479

Hi Howardroark,

Did you do it manually?

Isn't it tiresome?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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**Howardroark****Member**- Registered: 2010-10-10
- Posts: 382

Hi bobbym,

I Agree..

I come from a civilization which has given the world the number 0..

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