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

You are not logged in.

- Topics: Active | Unanswered

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 23,085

#379. If the coefficients of x[sup]2[/sup] and x[sup]3[/sup] in the expansion of

are the same, what is the value of 'a'?

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 23,085

#380. Find the sum of all the three digit numbers divisible by 7.

#381. If the p[sup]th[/sup], q[sup]th[/sup], and r[sup]th[/sup] terms of an Arithmetic Progression are a, b, and c respectively, what is the value of

#382. Find the sum

#383. Find the sum of the series

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi ganesh;

Answer given for #372 is not correct so here is mine.

*Last edited by bobbym (2009-07-17 15:04:49)*

**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.**

Offline

**BO****Member**- Registered: 2010-05-16
- Posts: 9

*Last edited by BO (2010-05-17 19:15:12)*

Offline

**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

**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.**

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 23,085

Hi,

I request I may be given some time to solve the problems.

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 23,085

The solution to #372 is given you. I am sorry.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi ganesh;

That is interesting for #372. Do you have a solution that I could look at? I have checked my answer by computer and it agrees with my answer of 2 not 6. Could you show me where I am going wrong? If you have the time. Thanks.

**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.**

Offline

**BO****Member**- Registered: 2010-05-16
- Posts: 9

I am also getting 2.

sorry about the bad latexing.

*Last edited by BO (2010-05-18 06:42:50)*

Offline

**BO****Member**- Registered: 2010-05-16
- Posts: 9

*Last edited by BO (2010-05-18 06:38:34)*

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 23,085

The solution to 377 is perfect. Well done, BO.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

Here is one that got missed!

**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.**

Offline

**smadhurbain@yahoo.in****Member**- Registered: 2010-11-14
- Posts: 2

divide 34 into two parts in such way that 4/7 of one part is equal to 2/5 of the other

Offline

**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 4,592

Hi Bobby,

*Last edited by phrontister (2010-11-14 23:44:03)*

"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****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi phrontister;

How are you! You are right! I missed the last part of the question.

**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.**

Offline

**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi smadhurbain@yahoo.in;

Welcome to the forum. You really should change your username. It is a security weakness.

In regards to your future questions. Please post them in Help Me. This thread is for Ganesh's puzzles.

**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.**

Offline

**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 4,592

Hi Bobby,

How are you!

Very well, thanks, but waaaaaay too busy with work atm (and have been for ages) to do much other than that. Hardly got time to scratch, and forum participation has been relegated to the back burner.

On a brighter note (and you may disagree with that), last week I met yet another mathematical physicist - this time through work - and we chatted puzzles. Of course I couldn't resist giving him 3 of my favourite puzzles (you know which - NOHOW, My YOB & Callous Count Crewell), plus another toughie that I'll post one day. He said he'd do them - or maybe his son who's doing maths at uni and likes maths puzzles will give 'em a go - but already 4 days have passed and I've received nary a word from either about any.

Oh well...

"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****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi phrontister;

Sorry. to hear that you will not be around. The mean part of me says what chance does a physi guy or his offspring have of knocking off one of your puzzles!

Also if you are going to keep running in to them people, I would get another job!

**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.**

Offline

**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi ganesh;

Back to the problems!

**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.**

Offline

**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,037

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

**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,037

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

**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,037

hi ganesh

*Last edited by anonimnystefy (2011-08-25 08:35:39)*

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

**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,037

hi ganesh

there are a lot of unsolved puzzles here:

*Last edited by anonimnystefy (2011-08-25 10:58:40)*

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

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 23,085

Hi anonimnystefy,

Thanks for replying the brain teasers. It would take a long time to check the veracity of all the solutions. I shall reply as soon as I can. Please give me enough time!

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi ganesh;

If you have time can you check from post #464 on. I am sorry for some cross chatter that when on at that point. I believe that phrontister's solution is better than mine.

Also, maybe the remaining unanswered questions could be brought to the bottom.

**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.**

Offline