Math Is Fun Forum

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

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

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

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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
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: dice probability using Tree Diagram

Hi jacks

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“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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