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

You are not logged in.

- Topics: Active | Unanswered

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,705

Do you have the book? It is on page 431 of the sixth edition and he gives 3 examples after the derivation.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,525

Is it anywhere in the 7th edition?

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: 86,705

Hi;

It is on p 483 in the seventh edition. Looks okay.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,705

Hi

Festisio wrote:

The calculation they use.. it makes a bunch of assumptions.. they are based on prior proofs..

So why would not use the formula he gave at the bottom? That is how he gets his answer.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

Offline

**fizzy-flow****Member**- Registered: 2013-06-04
- Posts: 1

hey guys i'm not sure how to solve this question and was hoping for someone to help me out :s

(i'm studying for an exam and i'm not sure how they got the answer or if its right or wrong)

thanks in advance

A "pair" of socks is two socks of the same colour. i have 17 identical red socks and 12 identical blue socks in a bag. how many socks must i pull out of the bag ( while i'm blindfolded) to be sure of getting two pairs of socks, of wither colour?

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,525

I would say the answer is 5.

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: 86,705

Hi;

I thought 18.

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,394

Hi fizzy-flow

Welcome to the forum.

If four are picked of the same colour then we're done so let's try hard to avoid that. Call the colours x and y.

So avoid xxxx and yyyy.

xxyy means we're done so let's avoid that too

So xxxy or yyyx are the only ways to be sure we haven't yet got two pairs.

So now pick another.

Four possibilities xxxyy or xxxyx or yyyxx or yyyxy

All of these result in two pairs, so I think 5 is the answer, too.

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,525

bobbym wrote:

Hi;

I thought 18.

Hi bobbym

Two socks of the same colour make a pair, not of different colours.

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

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,394

Maybe not in bobbym's world. One man's fashion is another man's individualism.

But even then, it'd have to be 19, to get R-B, R-B

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,525

True.

People like him actually wear green socks.

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

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,394

I had a strange internet moment.

I wanted to take the saying "One man's meat is another man's poison" and make it "One man's fashion is another man's .....?" What? I couldn't think of a word. So I went to an antonym dictionary but it wasn't much help. So I googled "antonym fashion" and got inundated with offers to sell me some.

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,525

Fashion doesn't seem like a noun with an antonym.

Speaking of antonyms and such, I have just been surprised by the fact that the adjective interested has two antonyms.

I think bobbym might also have some maroon socks.

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

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,394

Only two?

Antonym word of happy:

"depressed, discouraged, dissatisfied, miserable, morose, pained, sad, sorrowful, unhappy"

synonym-antonym.com

Bob

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,525

Two with different meanings.

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

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,394

I see what you mean. I'll work on it.

Back later.

Bob

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,525

Work on what?

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

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,394

hi Stefy,

These words are all antonyms of a certain word. What is it?

bright

light

sunny

clean

shiny

Bob

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,525

Are you sure those are all antonyms to that word? How is sunny opposite to that??

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

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,394

Yes. I looked up a word that had lots of meanings. Then I found the antonym for each meaning. That gave the list.

Bob

Offline

**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,848

Hi Bob,

Is this the answer?:

"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

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,394

hi Phro,

Well, I'll give it to you for the five words on show, but it wasn't the word I started with. You have earned the right to peek at the hidden 6th word now.

Bob

Offline

**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,848

Hi Bob,

"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

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,394

hi Phro

Another excellent try and yet not my word either.

I suppose this is the result of choosing a general purpose word. It has lots of meanings including attempt #2.

Bob

Offline

**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,848

Hi Bob,

Thought I had it with that last one.

Hmmm....

"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