BdMO National 2013: Primary 2, Junior 1

Discussion on Bangladesh Mathematical Olympiad (BdMO) National
BdMO
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BdMO National 2013: Primary 2, Junior 1

Unread post by BdMO » Fri Jan 10, 2014 1:12 am

Nazia’s mobile phone has a strange problem. Each time she sends an SMS, it is also sent to all the existing numbers of her call list. The actual recipient of the SMS is then added to her call list.. At some point, Nazia deleted her call list. The next SMS she sent was the $16^{th}$ SMS sent from her mobile phone. How many numbers were there in her call list before she deleted her call list?

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atiab jobayer
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Re: BdMO National 2013: Primary 2, Junior 1

Unread post by atiab jobayer » Fri Jan 24, 2014 10:59 am

:D I think it will be 15 day.because when she send the last message it was the 16th message after clearing message.

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*Mahi*
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Re: BdMO National 2013: Primary 2, Junior 1

Unread post by *Mahi* » Sat Jan 25, 2014 2:35 pm

Please do not use red color in general posts in forum, as it is generally associated and can be confused with warnings or notices.
Please read Forum Guide and Rules before you post.

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

Nur Muhammad Shafiullah | Mahi

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atiab jobayer
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Re: BdMO National 2013: Primary 2, Junior 1

Unread post by atiab jobayer » Thu Dec 04, 2014 10:24 am

*Mahi* wrote:Please do not use red color in general posts in forum, as it is generally associated and can be confused with warnings or notices.

But Mahi, I've used blue colour. Not RED.
math champion

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*Mahi*
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Re: BdMO National 2013: Primary 2, Junior 1

Unread post by *Mahi* » Thu Dec 04, 2014 9:08 pm

That was because I edited the post. Forgot to clarify that part, sorry.
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tanmoy
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Re: BdMO National 2013: Primary 2, Junior 1

Unread post by tanmoy » Thu Dec 04, 2014 10:27 pm

The answer is:$1+2+3+4+.......+15=120$
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Raiyan Jamil
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Re: BdMO National 2013: Primary 2, Junior 1

Unread post by Raiyan Jamil » Fri Dec 05, 2014 7:18 pm

I think there were 5 numbers. Because, after sending the first message, there will be 1 number in the call list . And in the next message, there will be 2 numbers in the call list and 3 messages in the message box(as 1+2=3). Then, going like this we will see that there are 5 numbers in the call list and 15 messages in the message box(as 1+2+3+4+5=15). And deleting all the numbers and sending a new message, then it will be the 16th message.
So, that is why I think there were 5 numbers. Someone please clarify if my answer is right or wrong.
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samiul_samin
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Re: BdMO National 2013: Primary 2, Junior 1

Unread post by samiul_samin » Sun Dec 31, 2017 8:20 am

the correct answer is 5.

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M. M. Fahad Joy
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Re: BdMO National 2013: Primary 2, Junior 1

Unread post by M. M. Fahad Joy » Sun Feb 18, 2018 10:43 am

samiul_samin wrote:
Sun Dec 31, 2017 8:20 am
the correct answer is 5.
Mr. Intelligent brother,
Why have you mixed the call list with message list?
You cannot cross the sea merely by standing and staring at the water.

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samiul_samin
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Re: BdMO National 2013: Primary 2, Junior 1

Unread post by samiul_samin » Sun Feb 18, 2018 10:45 am

M. M. Fahad Joy wrote:
Sun Feb 18, 2018 10:43 am
samiul_samin wrote:
Sun Dec 31, 2017 8:20 am
the correct answer is 5.
Mr. Intelligent brother,
Why have you mixed the call list with message list?
They are connected.See the previous posts again.

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