Math Is Fun Forum

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: [Discrete Math] Finals review problems in Probability

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

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: [Discrete Math] Finals review problems in Probability

Is it anywhere in the 7th edition?

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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
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: [Discrete Math] Finals review problems in Probability

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.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: [Discrete Math] Finals review problems in Probability

Hi

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.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

fizzy-flow

Member

Registered: 2013-06-04

Posts: 1

Re: [Discrete Math] Finals review problems in Probability

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?

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: [Discrete Math] Finals review problems in Probability

I would say the answer is 5.

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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
The knowledge of some things as a function of age is a delta function.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: [Discrete Math] Finals review problems in Probability

Hi;

I thought 18.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,644

Re: [Discrete Math] Finals review problems in Probability

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

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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: [Discrete Math] Finals review problems in Probability

Hi;

I thought 18.

Hi bobbym

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

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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
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,644

Re: [Discrete Math] Finals review problems in Probability

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

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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: [Discrete Math] Finals review problems in Probability

True.

People like him actually wear green socks.

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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
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,644

Re: [Discrete Math] Finals review problems in Probability

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

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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: [Discrete Math] Finals review problems in Probability

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.

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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
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,644

Re: [Discrete Math] Finals review problems in Probability

Only two?

Antonym word of happy:

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

synonym-antonym.com

Bob

---

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: [Discrete Math] Finals review problems in Probability

Two with different meanings.

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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
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,644

Re: [Discrete Math] Finals review problems in Probability

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

Back later.

Bob

---

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: [Discrete Math] Finals review problems in Probability

Work on what?

---

“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.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,644

Re: [Discrete Math] Finals review problems in Probability

hi Stefy,

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

bright
light
sunny
clean
shiny

Bob

---

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: [Discrete Math] Finals review problems in Probability

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

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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
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,644

Re: [Discrete Math] Finals review problems in Probability

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

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

phrontister

Real Member

From: The Land of Tomorrow

Registered: 2009-07-12

Posts: 4,895

Re: [Discrete Math] Finals review problems in Probability

Hi Bob,

Is this the answer?:

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"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

Bob

Administrator

Registered: 2010-06-20

Posts: 10,644

Re: [Discrete Math] Finals review problems in Probability

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

---

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

phrontister

Real Member

From: The Land of Tomorrow

Registered: 2009-07-12

Posts: 4,895

Re: [Discrete Math] Finals review problems in Probability

Hi Bob,

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"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

Bob

Administrator

Registered: 2010-06-20

Posts: 10,644

Re: [Discrete Math] Finals review problems in Probability

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

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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

phrontister

Real Member

From: The Land of Tomorrow

Registered: 2009-07-12

Posts: 4,895

Re: [Discrete Math] Finals review problems in Probability

Hi Bob,

Thought I had it with that last one.

Hmmm....

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"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