Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,610

Hidden message abuse!

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

Hi Shivamcoder3013;

In this thread because other people may want to work on the problems without actually seeing anyone else's work we use hidden replies.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,853

Hi Bobby,

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

Hi phrontister;

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,853

Hi Bobby,

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

Hi phrontister;

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,604

Hi bobbym

Got any expectation problems?

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

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,604

bobbym wrote:

New problem!

The probability of 1 kid is 1/6. Two kids is 1/3. Three kids is 1/3 and four kids is 1 / 6. Everyone gets married and has kids.

What is the chance that a couple has exactly 5 grandkids?A says 1 / 8

B says 4 / 129

C says (1 / 9)^4

D says ( 1 / 3 )^5

What if they have only one child and that child has 5 of his own childeren? We aren't given the probability of 5 children...

*Last edited by anonimnystefy (2012-11-04 10:43:52)*

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

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

Yikes! What in the name of a holy yoctometer are you talking about?

**In mathematics, you don't understand things. You just get used to them.**

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,604

Seems you missed post #1907.

I dug that problem from this thread...

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

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

Hmmm, and now you are getting your just reward!

**In mathematics, you don't understand things. You just get used to them.**

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,604

I don't understand...

Here lies the reader who will never open this book. He is forever dead.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

Do you not know my age? Are ye unaware of the aging process?

**In mathematics, you don't understand things. You just get used to them.**

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,604

bobbym wrote:

Do you not know my age? Are ye unaware of the aging process?

Well, you told me you were 9,99 and 92. I'm not sure which (if not all) version to believe. And yes, I am aware of it... What does that have to do with what I asked you?

Here lies the reader who will never open this book. He is forever dead.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

Well, us old people we forget things. Everyday I lose a couple of neurons and along with them a fact or two. I used to know what the heck that problem was talking about but I forgot. That is the price you pay for not answering problems promptly.

But if I had to bet my oatmeal on someone, I would bet on B! That there is one smart fella!

**In mathematics, you don't understand things. You just get used to them.**

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,604

bobbym wrote:

Well, us old people we forget things. Everyday I lose a couple of neurons and along with them a fact or two. I used to know what the heck that problem was talking about but I forgot. That is the price you pay for not answering problems promptly.

But if I had to bet my oatmeal on someone, I would bet on B! That there is one smart fella!

If you read the problem you will see that we are not given the probability that a couple has 5 children...

Here lies the reader who will never open this book. He is forever dead.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

I do not think you need that information. Four children could marry and produce 5 grandchildren could they not?

**In mathematics, you don't understand things. You just get used to them.**

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,604

But for the expected value, I need to include all possibilities of getting 5 grandchildren including having 5 children, each having 1 child and having only 1 child who has 5 children of his own. Thus, I need the information about the probability of having 5 children...

Here lies the reader who will never open this book. He is forever dead.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

Who said anything about expected value?

**In mathematics, you don't understand things. You just get used to them.**

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,604

Sorry, probability. But we still need the probability of having 5 children...

*Last edited by anonimnystefy (2012-11-04 11:12:26)*

Here lies the reader who will never open this book. He is forever dead.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

It is not necessary to know that. You can derive it from the other information.

**In mathematics, you don't understand things. You just get used to them.**

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,604

But then the problem gets much tougher...

Here lies the reader who will never open this book. He is forever dead.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

Not necessarily, if you remember the methods you have been taught. If you remember Richard.

**In mathematics, you don't understand things. You just get used to them.**

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,604

Feynmen? You only mentioned that story where he used DUIS.

Here lies the reader who will never open this book. He is forever dead.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 88,791

Nope! That story is not just for DUIS. It says a lot more than that. Feynmann is telling us something important there...

**In mathematics, you don't understand things. You just get used to them.**

Offline