Dhaka Secondary 2010/4

Problem for Secondary Group from Divisional Mathematical Olympiad will be solved here.
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BdMO
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Joined: Tue Jan 18, 2011 1:31 pm

Dhaka Secondary 2010/4

Unread post by BdMO » Fri Jan 21, 2011 7:05 pm

In how many ways can four different numbers be arranged so that they are not arranged in increasing or decreasing order?

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leonardo shawon
Posts: 169
Joined: Sat Jan 01, 2011 4:59 pm
Location: Dhaka

Re: Dhaka Secondary 2010/4

Unread post by leonardo shawon » Tue Jan 25, 2011 1:02 pm

4! - 2= 22

we can arrange 4 different numbers in 4! Ways. And there 2 numbers in increasing and decreasing order.. So the result is 4!-2=22
Ibtehaz Shawon
BRAC University.

long way to go .....

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