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## #1 2013-05-28 08:58:18

ElainaVW
Member
Registered: 2013-04-29
Posts: 563

### Probability problem.

Hello

There is a new game in town. You wager against the dealer who has a circle of circumference of one. Ten points are randomly drawn on the circumference. From each of the points, an arc is drawn counterclockwise with length one quarter. You win when the arcs cover the entire circumference.

It seems obvious that you need at least several arcs to cover the circumference. I am getting odds of 2 to 1. Is this a good bet?

Last edited by ElainaVW (2013-05-28 09:34:38)

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## #2 2013-05-28 09:31:39

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

Hi; ElainaVW;

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #3 2013-05-28 09:39:10

ElainaVW
Member
Registered: 2013-04-29
Posts: 563

### Re: Probability problem.

Hi Bobby

Thank you for the answer

What method did you use?

Do you know how to get the average number of gaps?

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## #4 2013-05-28 09:47:46

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

Hi;

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #5 2013-06-13 00:48:09

ElainaVW
Member
Registered: 2013-04-29
Posts: 563

### Re: Probability problem.

Hello:)

a,b,c,d are positive integers that are odd. There is a smallest fraction for that expression in the form

where x and y are coprime and x / y is positive. What is x + y?

Last edited by ElainaVW (2013-06-13 00:52:09)

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## #6 2013-06-13 00:58:25

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

Hi;

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #7 2013-06-13 02:02:13

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,018

### Re: Probability problem.

Hi ElainaVW

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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## #8 2013-06-14 00:17:05

ElainaVW
Member
Registered: 2013-04-29
Posts: 563

### Re: Probability problem.

bobbym and anonimnystefy

That is what I have.

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## #9 2013-06-14 00:20:15

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

Hi;

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #10 2013-07-15 00:31:39

Angie Pop
Member
Registered: 2013-07-14
Posts: 3

### Re: Probability problem.

With all "Probability posts on this Forum, none of the responses gives examples of explaining "Probability" in simplistic terms and in a manner that will allow kids to understand  "Probability - Chance and Data"in a manner thatwills simplistic and easy to understand by kids to- how can I do this?

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## #11 2013-07-15 00:41:00

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

I would have to disagree with that. I think there are a number of people here who can explain almost anything math related or anything else in simple terms.

Also, I have 8,9,12,13,14,16,18 year old young people that discuss math with me. I do not believe in talking down to people because they are young in age. In my time most of them would be considered adults. I can not disagree more with the "modern concept" that young people are babies and can not understand.

When someone posts I explain the relevant mathematics until he/she understands it as well as I do or gives up. All that is necessary is patience and confidence that younger people can absorb math much faster than older folks like myself.

If you give them a chance they will amaze you.

Probability is my specialty, I earned my living off of it most of my life. I can solve any darn probability probability anyone ever thought off or is likely to think of.
That is a conceit but it is a healthy one.

You have picked this post as an example. I urge you to look around a little more. ElainaVW is a genius, with an IQ of around 165 - 170. She likes to try to fry my brain with tough probability/combinatorics/computational questions. Of course she always fails but I admire her persistence.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #12 2013-07-15 02:21:32

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,018

### Re: Probability problem.

I can solve any darn probability probability anyone ever thought off or is likely to think of.

What about the 5x5 square problem?

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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## #13 2013-07-15 02:23:46

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

some guy wrote:

That is a conceit but it is a healthy one.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #14 2013-07-19 05:47:21

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

Hi;

Sorry for the double posting but someone requested the solution to this.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #15 2013-07-20 21:25:02

ElainaVW
Member
Registered: 2013-04-29
Posts: 563

### Re: Probability problem.

Hi bobbym;

Did you try those two formulas out? Didn't I ask you earlier in this thread?

Last edited by ElainaVW (2013-07-20 21:28:08)

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## #16 2013-07-20 21:31:40

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

Hi;

I do not have the paper that is mentioned so I had to do some simulations with the code provided. They check out as far as that.

Didn't I ask you earlier in this thread?

If you mean for the solution, yes you did. I did not post it then because I wanted to give other people a chance to work on it.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

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## #17 2013-07-28 02:33:30

ElainaVW
Member
Registered: 2013-04-29
Posts: 563

### Re: Probability problem.

Hello,

A random walk has two reflecting barriers at 0 and 3. By reflecting I mean that when they are reached the next move must be in the opposite direction. Each move is one unit right or left. Is that understandable?

My question is in how many ways can she finish on 3 if she makes 999 moves?:)

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## #18 2013-07-28 02:54:35

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

Hi;

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

Offline

## #19 2013-07-28 23:09:20

gAr
Member
Registered: 2011-01-09
Posts: 3,479

### Re: Probability problem.

Hi,

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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## #20 2013-07-28 23:25:55

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

Hi gAr;

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

Offline

## #21 2013-07-29 00:15:34

gAr
Member
Registered: 2011-01-09
Posts: 3,479

### Re: Probability problem.

Hi bobbym,

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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## #22 2013-07-29 00:18:03

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

Offline

## #23 2013-07-29 00:22:44

gAr
Member
Registered: 2011-01-09
Posts: 3,479

### Re: Probability problem.

That's right!

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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## #24 2013-07-29 00:32:38

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 106,362

### Re: Probability problem.

Hi;

I did run into someone else who had that same solution ( the only other two I could find like that ) and amazingly he had a similar name to you and is about your same age. He even lives around where you do. Just a coincidence, I would imagine.

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
No great discovery was ever made without a bold guess.

Offline

## #25 2013-07-29 00:39:42

gAr
Member
Registered: 2011-01-09
Posts: 3,479

### Re: Probability problem.

Hi,

That may be true!

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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