six faced dice

juantheron · 2011-12-17 04:53:39

a six faced fair dice is tnown until 1 comes , then the probability that 1 comes in even no. of trails is

Last edited by juantheron (2011-12-17 05:45:46)

bobbym · 2011-12-17 04:57:07

Hi juantheron;

You want the chance that a 1 comes up on an even throw?

anonimnystefy · 2011-12-17 05:21:49

hi guys

i got 5/11.

juantheron · 2011-12-17 05:25:02

yes answer given as

options

(1) 5/11 (2) 5/6 (3) 6/11 (4) 1/6

yes bobbym

explanation required

bobbym · 2011-12-17 05:29:18

Hi;

1) is correct.

juantheron · 2011-12-17 05:34:34

thanks bobbym,anonimnystefy

but how can i get this

bobbym · 2011-12-17 05:36:59

Hi;

Tree diagram and then you sum the series it produces. The one I have given above. If you do not understand please speak up.

anonimnystefy · 2011-12-17 05:45:17

hi bobbym

that is unnecessary.

juantheron

here's how you could do it with less work.

let p be the probability you want.

first we don't want a 1 on the first run,so the probability p will be:

p=5/6 +something.

now we have to see what that something is.

so that something represents the case when something other than a 1,so we write:

p=5/6 + 1/6 *(something)

this new something represents the probability that we get 1 from now on,and because we want one here we will calculate the probability for it:

p=5/6 + 1/6 *(1/6 + something)

this something is the case where a 1 didn't show up in neither first or second run so it's:

p=5/6 + 1/6 *(1/6 + 5/6*something)

and this final something represents the probability that we get a 1 from here on out and it's the same as p,so we are basically writing this:

p=5/6 + 1/6 *(1/6 + 5/6 * p)

now just find p and you got your probability

juantheron · 2011-12-17 05:51:14

thanks anonimnystefy but i did not understand in well manner

bobbym · 2011-12-17 06:04:29

Hi all;

anonimnystefy's idea is very nice but a little difficult to grasp that is why I gave the tree and geometric series answer. They are somewhat easier.

juantheron · 2011-12-17 06:06:56

yes you are right

bobbym would you like to explain your tree diagram

thanks

bobbym · 2011-12-17 06:11:46

Hi;

First let me say to anonimnystefy, very good solution!

juantheron:

It will take a while to draw a decent diagram, please hold.

anonimnystefy · 2011-12-17 06:27:26

well it's not my solution.i got the idea here:http://www.youtube.com/watch?v=_i_BONRM … Twkb65jI9G

bobbym · 2011-12-17 06:36:33

Hi anonimnystefy;

I already knew that but R.I.P.O.S.T.P.

To Juan;

Look at the diagram you are concerned with the nodes H,J and L. Count down the branches to see the patter that will form the series.

juantheron · 2011-12-17 06:50:56

thanks bobbym got it

bobbym · 2011-12-17 06:52:08

Hi;

Are you sure?

anonimnystefy · 2011-12-17 06:55:41

hi bobbym

what does R.I.P.O.S.T.P. stand for?

Last edited by anonimnystefy (2011-12-17 06:56:06)

bobbym · 2011-12-17 06:59:50

what does R.I.P.O.S.T.P. stand for?

Research Is Part Of Solving The Problem.

Hmmm, I would thought the other part of that statement would have caused you more consternation.

juantheron · 2011-12-17 07:18:23

Yes got it

Math Is Fun Forum

#1 2011-12-17 04:53:39

six faced dice

#2 2011-12-17 04:57:07

Re: six faced dice

#3 2011-12-17 05:21:49

Re: six faced dice

#4 2011-12-17 05:25:02

Re: six faced dice

#5 2011-12-17 05:29:18

Re: six faced dice

#6 2011-12-17 05:34:34

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#7 2011-12-17 05:36:59

Re: six faced dice

#8 2011-12-17 05:45:17

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#9 2011-12-17 05:51:14

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#10 2011-12-17 06:04:29

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#11 2011-12-17 06:06:56

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#12 2011-12-17 06:11:46

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#13 2011-12-17 06:27:26

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#14 2011-12-17 06:36:33

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#15 2011-12-17 06:50:56

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#16 2011-12-17 06:52:08

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#17 2011-12-17 06:55:41

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#18 2011-12-17 06:59:50

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#19 2011-12-17 07:18:23

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