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[Post New] 5 Feb 2012 18:08:00 IST
   Subject: A student is allowed to select at most n books from a collection of (2n+1) books. If the total n
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Siddhant chaudhary (0)

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A student is allowed to select at most n books from a collection of (2n+1) books. If the total number of ways in which he can select a book is 63 . Find the value of n .
    
[Post New] 5 Feb 2012 18:42:23 IST
   Subject: Combination
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Vishal U. Karve (205)

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2n+1C1+2n+1C2+...+2n+1Cn is the required no. of ways.

Simplifying...

=1/2 [2n+1C1+2n+1C2+...+2n+1C2n]

=1/2[22n+1-2]

=22n-1

Given,

22n-1=63

22n=64

22n=26

n=3
Knowledge is power.
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