BdMO National Secondary 2010#1

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samiul_samin
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BdMO National Secondary 2010#1

Unread post by samiul_samin » Fri Feb 22, 2019 11:00 pm

There are $20$ people in a party excluding you.It is known that you know the same number of people as you don't know.How many of them do you know?

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samiul_samin
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Re: BdMO National Secondary 2010#1

Unread post by samiul_samin » Fri Feb 22, 2019 11:40 pm

Answer:$10$
Let,
Know=don't know=$n$
So,
$n+n=20\Rightarrow 2n=20 \Rightarrow n=10$

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