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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,606

Oh.

```
list = {300, 250, 175, 100, 75, 50, 25, 15, 7, 3, 1}
SecondPick[tickets_] := Sum[i/1001*tickets/(1001 - i), {i, Delete[list, Position[list, tickets]]}];
```

*Last edited by anonimnystefy (2013-05-02 07:11:41)*

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,882

Code, code, give me code! Okay, thank you.

Code, code, a thousand lines of code. I'd rather die then debug it. Sung to the tune of "No, no, a thousand times no. I'd rather die then say yes."

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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I am not sure what you want.

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Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,882

Nothing, just singing an old song with my improved lyrics.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,606

Have you looked at the code?

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Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,882

I just copied it to my notebook that deals with this problem.

I must warn you that I am missing a couple of great abilities that God in his infinite wisdom decided not to bestow on me.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,606

What are those abilities?

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
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The list appears endless but the one that applies is that I never could read code written by someone else.

**In mathematics, you don't understand things. You just get used to them.**

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,606

Give me a few minutes to eat. When I get back, I will explain it a bit.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
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Very good, I will eat and continue to explore mythological creatures from Serbia.

**In mathematics, you don't understand things. You just get used to them.**

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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Mythological creatures? Like which?

To be honest, I never took much interest into Slavic mythology.

Now, for the code...

I am just summing P(second pick by n|first pick by i).

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
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I see that. But my general approach to computing the exact numbers here would be to tree it.

**In mathematics, you don't understand things. You just get used to them.**

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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Tree it? How?

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**bobbym****Administrator**- From: Bumpkinland
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You aware that Markov chains and gf's can be compact representations of trees?

There is just one tiny little, itsy bitsy problem...

**In mathematics, you don't understand things. You just get used to them.**

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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I do not know how useful Markov chains are here. The probabilities change for different previous picks.

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**bobbym****Administrator**- From: Bumpkinland
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Exact a mundo! GF's will have the same problem. But if you had a big piece of paper you could do it...

**In mathematics, you don't understand things. You just get used to them.**

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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I do not think it will be enough for picks higher than the second.

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**bobbym****Administrator**- From: Bumpkinland
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Nope, if I had a big piece of paper, I could just enumerate the entire tree. From beginning to end.

What I am getting at is how to do this using M and whatever structure is available. How to draw it without drawing. Now it is obvious we could use 11 nested loops but we should strive to use something a bit more elegant than that.

**In mathematics, you don't understand things. You just get used to them.**

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**anonimnystefy****Real Member**- From: The Foundation
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Well, Markov chains require the probabilities to stay the same, but maybe we can do something with GF's?

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**bobbym****Administrator**- From: Bumpkinland
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First, I am trying to work out the answer using programming.

**In mathematics, you don't understand things. You just get used to them.**

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**anonimnystefy****Real Member**- From: The Foundation
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That will be hard.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
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For instance:

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**anonimnystefy****Real Member**- From: The Foundation
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How'd you get those?

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**bobbym****Administrator**- From: Bumpkinland
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Wrote a little program to do it for me.

As you can see all answers are close to my simulation.

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
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Can you post the program code?

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