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## #2351 2012-12-14 22:01:15

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 98,295

### Re: Oral puzzles

Hi;

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

If it ain't broke, fix it until it is. Thinking is cheating.

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## #2352 2012-12-15 19:10:30

ganesh
Moderator
Registered: 2005-06-28
Posts: 18,127

### Re: Oral puzzles

Hi bobbym,

The solution #1674 is correct. Neat work!

#1675. Find the sum of all natural numbers less than 200 which are divisible by 5.

The divergent series are the invention of the devil, and its a shame to base on them any demonstration whatsoever - Neils Henrik Abel.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it - Samuel Johnson.

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## #2353 2012-12-15 21:17:51

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 98,295

### Re: Oral puzzles

Hi ganesh;

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

If it ain't broke, fix it until it is. Thinking is cheating.

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## #2354 2012-12-16 19:26:18

ganesh
Moderator
Registered: 2005-06-28
Posts: 18,127

### Re: Oral puzzles

Hi bobbym,

The solution #1675 is perfect. Good work!

#1676. Find the sum of all the natural numbers between 200 and 300 which are divisible by 4.

The divergent series are the invention of the devil, and its a shame to base on them any demonstration whatsoever - Neils Henrik Abel.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it - Samuel Johnson.

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## #2355 2012-12-16 21:54:01

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 98,295

### Re: Oral puzzles

Hi;

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

If it ain't broke, fix it until it is. Thinking is cheating.

Offline

## #2356 2012-12-17 18:29:40

ganesh
Moderator
Registered: 2005-06-28
Posts: 18,127

### Re: Oral puzzles

Hi bobbym,

The solution #1676 is perfect. Neat work!

#1677. Find the Arithmetic Progression whose sum to n terms is 2n[sup]2[/sup] + 2. (Find the values of the AP)

The divergent series are the invention of the devil, and its a shame to base on them any demonstration whatsoever - Neils Henrik Abel.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it - Samuel Johnson.

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## #2357 2012-12-17 21:28:37

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 98,295

### Re: Oral puzzles

Hi ganesh;

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

If it ain't broke, fix it until it is. Thinking is cheating.

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## #2358 2012-12-18 20:07:26

ganesh
Moderator
Registered: 2005-06-28
Posts: 18,127

### Re: Oral puzzles

Hi bobbym,

#1678. The houses of a row are numbered consecutively from 1 to 49. Show that there is a value of x such that the sum of the numbers of the houses preceding the house numbered x is equal to the sum of the numbers of the following it. Find this value of x.

The divergent series are the invention of the devil, and its a shame to base on them any demonstration whatsoever - Neils Henrik Abel.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it - Samuel Johnson.

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## #2359 2012-12-18 22:04:48

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 98,295

### Re: Oral puzzles

Hi ganesh;

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

If it ain't broke, fix it until it is. Thinking is cheating.

Offline

## #2360 2012-12-19 18:46:11

ganesh
Moderator
Registered: 2005-06-28
Posts: 18,127

### Re: Oral puzzles

Hi bobbym,

The solution #1678 is correct. Marvelous!

#1679. Find a[sub]30[/sub] - a[sub]20[/sub] for the Arithmetic Progression : a, a + d, a + 2d, a + 3d, ......

The divergent series are the invention of the devil, and its a shame to base on them any demonstration whatsoever - Neils Henrik Abel.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it - Samuel Johnson.

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## #2361 2012-12-19 20:23:43

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 98,295

### Re: Oral puzzles

Hi ganesh;

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

If it ain't broke, fix it until it is. Thinking is cheating.

Offline

## #2362 2012-12-20 18:47:43

ganesh
Moderator
Registered: 2005-06-28
Posts: 18,127

### Re: Oral puzzles

Hi bobbym,

The solution #1679 is correct. Good work!

#1680. Two Arithmetic Progressions have the same common difference. The difference between their 100th term is 111222333. What is the difference between their millionth terms?

The divergent series are the invention of the devil, and its a shame to base on them any demonstration whatsoever - Neils Henrik Abel.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it - Samuel Johnson.

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## #2363 2012-12-20 21:12:17

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 15,954

### Re: Oral puzzles

Hi ganesh

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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## #2364 2012-12-20 21:35:55

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 98,295

### Re: Oral puzzles

Hi ganesh;

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

If it ain't broke, fix it until it is. Thinking is cheating.

Offline

## #2365 2012-12-20 23:58:11

ganesh
Moderator
Registered: 2005-06-28
Posts: 18,127

### Re: Oral puzzles

Hi anonimnystefy and bobbym,

The solution #1680 is correct. Well done!

#1681. Which term of the Arithmetic Progression 21, 18, 15, ..... is 0?

The divergent series are the invention of the devil, and its a shame to base on them any demonstration whatsoever - Neils Henrik Abel.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it - Samuel Johnson.

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## #2366 2012-12-21 00:01:05

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 98,295

### Re: Oral puzzles

Hi;

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

If it ain't broke, fix it until it is. Thinking is cheating.

Offline

## #2367 2012-12-21 06:38:06

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 15,954

### Re: Oral puzzles

Hi ganesh

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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## #2368 2012-12-21 18:52:15

ganesh
Moderator
Registered: 2005-06-28
Posts: 18,127

### Re: Oral puzzles

Hi bobbym and anonimnystefy,

The solution #1681 is correct. Neat work!

#1682. Find the 30th term of the Arithmetic Progression 10, 7, 4, ......

The divergent series are the invention of the devil, and its a shame to base on them any demonstration whatsoever - Neils Henrik Abel.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it - Samuel Johnson.

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## #2369 2012-12-21 22:48:22

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 98,295

### Re: Oral puzzles

Hi;

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

If it ain't broke, fix it until it is. Thinking is cheating.

Offline

## #2370 2012-12-22 19:21:13

ganesh
Moderator
Registered: 2005-06-28
Posts: 18,127

### Re: Oral puzzles

Hi bobbym,

The solution #1682 is correct. Neat work!

#1683. If a = -18, n = 10, a[sub]n[/sub] = 0, find d.

The divergent series are the invention of the devil, and its a shame to base on them any demonstration whatsoever - Neils Henrik Abel.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it - Samuel Johnson.

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## #2371 2012-12-22 22:01:50

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 98,295

### Re: Oral puzzles

Hi ganesh;

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

If it ain't broke, fix it until it is. Thinking is cheating.

Offline

## #2372 2012-12-22 23:16:25

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 15,954

### Re: Oral puzzles

Hi ganesh

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.

Offline

## #2373 2012-12-23 18:51:07

ganesh
Moderator
Registered: 2005-06-28
Posts: 18,127

### Re: Oral puzzles

Hi bobbym and anonimnystefy,

The solution #1683 is perfect. Neat job!

#1684. If a = 3.5, d = 0, n = 105, find a[sub]n[/sub].

The divergent series are the invention of the devil, and its a shame to base on them any demonstration whatsoever - Neils Henrik Abel.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it - Samuel Johnson.

Offline

## #2374 2012-12-23 19:13:29

bobbym
From: Bumpkinland
Registered: 2009-04-12
Posts: 98,295

### Re: Oral puzzles

Hi;

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

If it ain't broke, fix it until it is. Thinking is cheating.

Offline

## #2375 2012-12-24 19:12:03

ganesh
Moderator
Registered: 2005-06-28
Posts: 18,127

### Re: Oral puzzles

Hi bobbym,

The solution #1684 is correct. Good work!

#1685. Find the number of odd numbers between 0 and 50.

The divergent series are the invention of the devil, and its a shame to base on them any demonstration whatsoever - Neils Henrik Abel.
Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it - Samuel Johnson.

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