Delhi Police Constable 2008 Paper

Question : 92 of 100

Marks: +1, -0

When a party ends, total handshakes are 28.If each one present in the party shakes hand once with all the rest, find out the number of people in the party.

Validate

Solution:

^{n}C_2=28

⇒{n(n-1)}/2=28

⇒n^2-n-56=0

⇒(n-8)(n+7)=0

only on taking positive value n = 8
i.e., desired number of people = 8

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