## BdMO National 2012: Higher Sec, Sec, Junior 01, Primary 02

Moon
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### BdMO National 2012: Higher Sec, Sec, Junior 01, Primary 02

Problem:
Subrata writes a letter to Ruponti every day (in successive intervals of $24$ hours) from Korea. But Ruponti receives the letters in intervals of $25$ hours. What is the number of the letter Ruponti receives on the $25^{th}$ day?
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Blue Blood Prince
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### Re: BdMO National 2012: Higher Sec, Sec, Junior 01, Primary

Ruponti receives no letter on the 25^{th} day

nafistiham
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### Re: BdMO National 2012: Higher Sec, Sec, Junior 01, Primary

if the counting starts subrata's sending it is $24^{th}$
but, if it starts with ruponti's recieving, it is $25^{th}$
i am still confused.
$\sum_{k=0}^{n-1}e^{\frac{2 \pi i k}{n}}=0$
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abdullah al munim
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### Re: BdMO National 2012: Higher Sec, Sec, Junior 01, Primary

If the first letter is sent before the 24 th hour,then the number of letters is 24.and if the first letter is sent on the 24th hour then it is 23.

*Mahi*
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### Re: BdMO National 2012: Higher Sec, Sec, Junior 01, Primary

এইটা সম্পর্কে ধনঞ্জয় বিশ্বাসের অমর উক্তি-
"দিন কি $[)$ এইরকম নাকি $(]$ এইরকম?"

Use $L^AT_EX$, It makes our work a lot easier!

nafistiham
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### Re: BdMO National 2012: Higher Sec, Sec, Junior 01, Primary

*Mahi* wrote:এইটা সম্পর্কে ধনঞ্জয় বিশ্বাসের অমর উক্তি-
"দিন কি $[)$ এইরকম নাকি $(]$ এইরকম?"
বুঝলাম না । এইটার সাথে ওইটার সম্পর্ক কি ?
$\sum_{k=0}^{n-1}e^{\frac{2 \pi i k}{n}}=0$
Using $L^AT_EX$ and following the rules of the forum are very easy but really important, too.Please co-operate.

*Mahi*
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### Re: BdMO National 2012: Higher Sec, Sec, Junior 01, Primary

প্রশ্নটার অর্থ হইল "দিন" কি ধরণের interval, রাত ১২ টায় open না closed.

Use $L^AT_EX$, It makes our work a lot easier!

nafistiham
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### Re: BdMO National 2012: Higher Sec, Sec, Junior 01, Primary

২৫ তম দিনে কোন চিঠি পাবে না ।
$\sum_{k=0}^{n-1}e^{\frac{2 \pi i k}{n}}=0$
Using $L^AT_EX$ and following the rules of the forum are very easy but really important, too.Please co-operate.

Abid
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### Re: BdMO National 2012: Higher Sec, Sec, Junior 01, Primary

সুব্রত চিঠি পাঠাই ২৪ ঘণ্টা পর মানে ১ দিন পর
রুপন্তি পাই ২৫ ঘণ্টা পর অর্থাৎ {১ + (১/২৪) }

n দিন পর সুব্রত চিঠি পাঠাই আর রুপন্তি পাই {n + (n/24)} দিনে

এভাবে তো ২৫ তম দিনে রুপন্তি যে চিঠি পাই শেতা সুব্রত এর ২৪ তম চিঠি......।/??????????? কিংকর্তব্যবিমুঢ়............

turash
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### Re: BdMO National 2012: Higher Sec, Sec, Junior 01, Primary

rupani 25 number chiti ti pay 26 th day er 1am e. 24 number chiti pay tar ager din & ek hour age.