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Consider that the 4th person chose dish X.

The Probability that the 1st Person chose dish X is 1/5.

The Probability that the 2nd Person chose dish X is 1/5.

The Probability that the 3rd Person chose dish X is 1/5.

Therefore, the probability that anyone has chosen X before is 3/5.

So, the possibility that the dish is previously not chosen is 2/5

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'Humanity is still kept intact. It remains within.' -Alokananda

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,547

Is that the exact question?

**In mathematics, you don't understand things. You just get used to them.I have the result, but I do not yet know how to get it.All physicists, and a good many quite respectable mathematicians are contemptuous about proof.**

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I would say yes, because the answer you gave me works

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'Humanity is still kept intact. It remains within.' -Alokananda

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,311

Agnishom wrote:

The Probability that the 1st Person chose dish X is 1/5.

The Probability that the 2nd Person chose dish X is 1/5.

The Probability that the 3rd Person chose dish X is 1/5.

Therefore, the probability that anyone has chosen X before is 3/5.

That method is faulty. If there were 5 people before D, you would end up with 5/5 and no chance for D.

I'll work on an analytic method.

Bob

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

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,547

Must be different for me and you then. Mine requests a + b in a / b.

**In mathematics, you don't understand things. You just get used to them.I have the result, but I do not yet know how to get it.All physicists, and a good many quite respectable mathematicians are contemptuous about proof.**

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bob bundy wrote:

Agnishom wrote:The Probability that the 1st Person chose dish X is 1/5.

The Probability that the 2nd Person chose dish X is 1/5.

The Probability that the 3rd Person chose dish X is 1/5.

Therefore, the probability that anyone has chosen X before is 3/5.That method is faulty. If there were 5 people before D, you would end up with 5/5 and no chance for D.

I'll work on an analytic method.

Bob

Ya, so... What to do?

Hi bobbym,

They ask me for a + b too

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'Humanity is still kept intact. It remains within.' -Alokananda

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,547

You can not add them up.

**In mathematics, you don't understand things. You just get used to them.I have the result, but I do not yet know how to get it.All physicists, and a good many quite respectable mathematicians are contemptuous about proof.**

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Then?

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'Humanity is still kept intact. It remains within.' -Alokananda

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 84,547

I have the result, but I do not yet know how to get it.

All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,311

hi

I get that too by my own method and a general formula too.

Bob

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

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THanks

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'Humanity is still kept intact. It remains within.' -Alokananda

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