Dhaka Divisional Higher Secondary 2011

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Please don't post problems (by starting a topic) in the "X: Solved" forums. Those forums are only for showcasing the problems for the convenience of the users. You can always post the problems in the main Divisional Math Olympiad forum. Later we shall move that topic with proper formatting, and post in the resource section.
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Moon
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Dhaka Divisional Higher Secondary 2011

Unread post by Moon » Fri Jan 28, 2011 8:01 pm

Finally BdMO 2011 problem set is available. Starting from the Higher Secondary. :)

Challenge yourself and have fun!
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Dhaka Higher Secondary Divisional 2011
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Hasib
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Re: Dhaka Divisional Higher Secondary 2011

Unread post by Hasib » Fri Jan 28, 2011 8:09 pm

Shit! I have no pdf reader for my mobile. Please give a link, please!
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Tahmid Hasan
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Re: Dhaka Divisional Higher Secondary 2011

Unread post by Tahmid Hasan » Fri Jan 28, 2011 8:14 pm

bhai1st taans ki 108?
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Re: Dhaka Divisional Higher Secondary 2011

Unread post by Moon » Fri Jan 28, 2011 8:16 pm

Ans issa kore muche disi ;)...bcz you have to discuss them in the forum. That is the best way to learn problem solving.You have to discuss.
@hasib: I am going to post the problems soon. (within an hour) So don't worry. :)
"Inspiration is needed in geometry, just as much as in poetry." -- Aleksandr Pushkin

Please install LaTeX fonts in your PC for better looking equations,
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Tahmid Hasan
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Re: Dhaka Divisional Higher Secondary 2011

Unread post by Tahmid Hasan » Fri Jan 28, 2011 9:15 pm

could solve only 6 probs in 1:15 hours :'(
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Hasib
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Re: Dhaka Divisional Higher Secondary 2011

Unread post by Hasib » Fri Jan 28, 2011 9:21 pm

Moon vai- please, quick give me. Felt crazy!
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Re: Dhaka Divisional Higher Secondary 2011

Unread post by Tahmid Hasan » Fri Jan 28, 2011 9:47 pm

soln for num 1:
i've done it with worst luck method. there are $10$ different size of gold coins, at most $41$ coins can be of same size. similarly at most $64$ silver coins can be of same size. If we take $64+41+1$ coins, we will be sure that either we have picked at least two gold coins of different size or at least two silver coins of different size. In both cases, we are getting two coins which are different both in size and colour. so the ans is $106$
:ugeek:
Last edited by Tahmid Hasan on Sat Jan 29, 2011 7:29 pm, edited 4 times in total.
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Tahmid Hasan
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Re: Dhaka Divisional Higher Secondary 2011

Unread post by Tahmid Hasan » Fri Jan 28, 2011 9:56 pm

no.2:the 3 digit numbers with the three same digits are 111,222,333,....999
trial and error
ans:2
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Chorom Boka
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Re: Dhaka Divisional Higher Secondary 2011

Unread post by Chorom Boka » Fri Jan 28, 2011 10:00 pm

Frst prblm: 117

Scnd: 12

Thrd: B= empty set

4th: a=12

5th: R= -1

7th: 2/3


Vul hoile bekkha dio (Mun)

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Re: Dhaka Divisional Higher Secondary 2011

Unread post by abir91 » Fri Jan 28, 2011 10:15 pm

Tahmid: Your first solution was correct. The second one is wrong.

Don't worry about how many you solved during time pressure. Mathematics is not a sport. It is meant to be enjoyed.

I also failed to solve all of the problems in 75 minutes :)
Abir

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