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(#M40034696) A WEBSITE Numerical Ability question Keep an EYE

At a party, everyone shook hands with everybody else. There were 66 handshakes. How many people were at the party?

Asked In A website karthika kumar (11 years ago)

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ram kiran  (11 years ago)

12 people.
n=11 (when there are 12 people, there will be only 11 hand shake)
For checking it=n(n+1)/2=11*12/2=6*11=66 shakehands

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Kavita Tewani  (11 years ago)

If there are 4 people the number of hand shakes will be:
3 (first person shakes hand with every one except with himself) +
2( second person shakes hand with every one except himself and the first 1)=
1(third person shakes hand with only last person )+
0 (as last person has already shook hands with every 1)
so total number of hand shakes=3+2+1+0=6=3*4/2=n(n+1)/2 (Sum of natural number)
Substitute n(n+1)/2=66, you get 11.
Now add 1 as for the last person as person.
So the answer is 12.

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Swathi  (11 years ago)

n(n-1)/2=66
n(n-1)=132
then n value is 12.

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