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#1 2014-05-22 21:20:04

CandyManSugar
Member
Registered: 2014-05-22
Posts: 3

Probabality

Two coins are tossed. One is unbiased and the other one is biased with the occurrence of a head being twice as likely as the occurrence of a tail? What is the probability of observing at least 1 tail?

(A) 1/3
(B) 2/3
(C) 3/8
(D) None of these

I would be glad if someone would teach me how to solve such problem.

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#2 2014-05-22 23:06:57

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

Re: Probabality

Hi;

What have you done to solve this problem? Do you have some work that I can see where you are going wrong? Do you know how to make a tree for the problem?


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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#3 2014-05-23 02:16:40

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: Probabality

Hi GiB;

Thanks for the answer

Last edited by Agnishom (2014-05-23 02:18:18)


'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'
I'm not crazy, my mother had me tested.

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#4 2014-05-23 03:50:41

CandyManSugar
Member
Registered: 2014-05-22
Posts: 3

Re: Probabality

bobbym wrote:

Hi;

What have you done to solve this problem? Do you have some work that I can see where you are going wrong? Do you know how to make a tree for the problem?

I don't know how to solve some problems and how to make a tree you are talking about.

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#5 2014-05-23 04:07:31

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

Re: Probabality

Okay, hold on and I will enumerate for you.

Label the first coins sides h and t and since it is a fair coin h has a probability of 1 / 2 and so does t.

Label the second coins sides h1 and t1 and since the probability of heads is twice the probability of tails with this coin then h1 = 2 / 3 and t1 = 1 / 3.

Do you follow up to here?


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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