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## #1 2012-12-19 05:16:57

jacks
Member
Registered: 2012-11-21
Posts: 132

### dice probability using Tree Diagram

A fair dice is rolled . the probability that the first time one occur at even no. of trails

Can any one explain me using Tree Diagram.

Thanks

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## #2 2012-12-19 05:53:23

bob bundy
Moderator
Registered: 2010-06-20
Posts: 7,948

### Re: dice probability using Tree Diagram

hi jacks,

You may throw a one straight away, or on throw 2, or on throw 3, or on throw 4, or ...........

See diagram.

P(one at first throw) = 1/6
P(one at second throw) = 5/6 times 1/6 = 5/36
P(one at third throw) = 5/6 x 5/6 x 1/6 = 25/216

etc etc.

As this goes on for ever you need to know how to do the sum to infinity of a geometric progression.  Post again if you want help with that.

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #3 2012-12-19 06:00:21

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,030

### Re: dice probability using Tree Diagram

Hi jacks

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
The knowledge of some things as a function of age is a delta function.

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