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**Al-Allo****Member**- Registered: 2012-08-23
- Posts: 294

I have just a little question about this : If I toss a coin 5 times, what is the probability of getting 4 tails and 1 head ? I think the answer is 5/32 ? Is this any good ? THanks

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,544

5/32 is correct.

Here lies the reader who will never open this book. He is forever dead.

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

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**Al-Allo****Member**- Registered: 2012-08-23
- Posts: 294

Omg im happy to know that because in my book it says its 4/32 ?!? And here is another one, what is the prob that it will land 3 times on head and 2 times on tails ? I got 9/32 but in my book it says 8/32 ?!? There is always 1 of difference, we could say it's an error ? Thanks !

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,426

hi Al-Allo

Welcome to the forum.

Stay on-line. I'm just working it out.

1 5 10 10 5 1

It should be 10/32

hhhtt, hhtht, hhtth, hthht, hthth, htthh, thhht, thhth, ththh, tthhh

Bob

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

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**Al-Allo****Member**- Registered: 2012-08-23
- Posts: 294

oh yes you're right. i noticed i missed one, so thanks ! finaly, my book wasnt right ! thanks you two !

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 87,238

Hi Al-Allo;

Both of those are binomial distribution problems. What is the name of the book?

**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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**Al-Allo****Member**- Registered: 2012-08-23
- Posts: 294

It's not written in English ... ^^ Even, it's only exercises, nothing more lol

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