Dhaka Junior 2011/2

Problem for Junior Group from Divisional Mathematical Olympiad will be solved here.
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Dhaka Junior 2011/2

Unread post by Moon » Wed Feb 02, 2011 8:21 am

2. In a box there are $420$ balls of $20$ different colors. What is the minimum number of balls one need to pick so that he can be sure of having at least two balls of same colors?
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Mehfuj Zahir
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Re: Dhaka Junior 2011/2

Unread post by Mehfuj Zahir » Wed Feb 02, 2011 11:30 am

At least 21 balls needed

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Re: Dhaka Junior 2011/2

Unread post by ataher.sams » Wed Nov 30, 2011 6:49 pm

Yes.. 21 balls..

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