Candles....(From CMC test)

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Abdul Muntakim Rafi
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Re: Candles....(From CMC test)

Unread post by Abdul Muntakim Rafi » Sun Dec 18, 2011 11:22 pm

Bangla please...
PS: I can't understand the question :(
Man himself is the master of his fate...

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bristy1588
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Re: Candles....(From CMC test)

Unread post by bristy1588 » Mon Dec 19, 2011 12:02 am

Rafi,
Nowshin er kache $n$ sonkhok mombati ase. 1st din e, Noushin jekono 1 ta mombati 1 ghonta jalay, 2nd in e she jekono ekta mombati r prottekta 2 ghonta jalay, 3rd din e, she 3 ta mombati 3, prottektake 3 ghonta jalay,, evabe n tomo dine she n ta mombati n ghonta jalay, n-din sheshe, protita mombati shoman poriman jalano hoise. Tahole $n$ koto??
Bristy Sikder

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Abdul Muntakim Rafi
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Re: Candles....(From CMC test)

Unread post by Abdul Muntakim Rafi » Mon Dec 19, 2011 12:04 pm

Bristy,Thank you very much... :D
Man himself is the master of his fate...

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nafistiham
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Re: Candles....(From CMC test)

Unread post by nafistiham » Mon Dec 19, 2011 1:55 pm

excuse me, what is a CMC test.unfortunately, i don't know.
\[\sum_{k=0}^{n-1}e^{\frac{2 \pi i k}{n}}=0\]
Using $L^AT_EX$ and following the rules of the forum are very easy but really important, too.Please co-operate.
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sm.joty
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Re: Candles....(From CMC test)

Unread post by sm.joty » Mon Dec 19, 2011 4:39 pm

Canadian Mathematics Contest. may be...
হার জিত চিরদিন থাকবেই
তবুও এগিয়ে যেতে হবে.........
বাধা-বিঘ্ন না পেরিয়ে
বড় হয়েছে কে কবে.........

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bristy1588
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Re: Candles....(From CMC test)

Unread post by bristy1588 » Mon Dec 19, 2011 7:24 pm

Joty, Hehe he .. Its not Canadian Math Contest,, Its Chittagong Math Circle
Bristy Sikder

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sm.joty
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Re: Candles....(From CMC test)

Unread post by sm.joty » Mon Dec 19, 2011 9:23 pm

Woww..... :lol: :lol: :lol: :lol: :lol: :lol:
I'm a fool.
But there is actually a contest named Canadian Mathematics Contest. :mrgreen:
amazing..... :lol: :lol:
হার জিত চিরদিন থাকবেই
তবুও এগিয়ে যেতে হবে.........
বাধা-বিঘ্ন না পেরিয়ে
বড় হয়েছে কে কবে.........

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bristy1588
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Re: Candles....(From CMC test)

Unread post by bristy1588 » Mon Dec 19, 2011 11:07 pm

Any idea about the Solution??
Bristy Sikder

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sm.joty
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Re: Candles....(From CMC test)

Unread post by sm.joty » Thu Dec 22, 2011 10:12 pm

এই সমস্যাটার কাছাকাছি একটা সমস্যা এবার Notre Dam এর অলিম্পিয়াডে আসছিল। পারি নাই। :cry: :cry: :cry:
So no idia.
হার জিত চিরদিন থাকবেই
তবুও এগিয়ে যেতে হবে.........
বাধা-বিঘ্ন না পেরিয়ে
বড় হয়েছে কে কবে.........

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Abdul Muntakim Rafi
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Re: Candles....(From CMC test)

Unread post by Abdul Muntakim Rafi » Sat Dec 24, 2011 2:11 am

In n days each candle will be lit for
\[\frac{(n+1)(2n+1)}{6}=k\]
Here k denotes the number of hours each candle would be lit which is obviously a positive integer...

That implies
\[2n^2+3n+1=6k\]
$6k$ is an even number... We can't get that if n is even... so let's assume n is odd... $n=2x+1$

Then we will get to the point
\[2(2x+1)^2+3(2x+1)+1=6k\]
\[2(x+1)(4x+3)=6k\]
\[(x+1)(4x+3)=3k\]
Now we need to prove this equation holds only for x=0 which implies n=1... Now the question is how do we prove this?
PS: I am just taking a guess it is possible only for n=1... Well if we can't prove this, we need to think otherwise..
Man himself is the master of his fate...

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