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Can I Get Answer To This ? by caljulator(m): 10:33pm On Dec 15, 2016
Got this question in an interview recently that got me puzzled
"If everybody at a party shook hand with each other and there are total of 66 handshakes, How many people attended the party ? Am sure there are gurus in the house
Re: Can I Get Answer To This ? by Godwin0420(m): 12:24pm On Dec 16, 2016
12 people
Re: Can I Get Answer To This ? by caljulator(m): 9:56pm On Dec 16, 2016
Godwin0420:
12 people
please how come
Re: Can I Get Answer To This ? by Nobody: 10:16pm On Dec 16, 2016
Godwin0420:
12 people
correct, oga boss na you o
Re: Can I Get Answer To This ? by Nobody: 10:37pm On Dec 16, 2016
caljulator:


please how come
I really want godwin0420 to explain how he got the answer. I know for a fact that he is right, you can confirm by solving it backwards.
I also solved it myself but it took me a whole lot of time and I don't know how to explain it well, I sha developed this method and i'm pretty sure it works for all cases though it is a bit cumbersome and lengthy
1+2+...+(x-1) = y,
where x is the number of people in the party and y is the total number of handshakes. assuming the total number of people shaked each other just ones.

so therefore we have, 1+2+3+4+5+6+7+8+9+10+11=66,
from this you can infer that (x-1)=11,
so therefore x = 12,
it works for all cases,
e.g if we had 6 hand shakes in all it means
1+2+3=6,
so therefore (x-1)=3, then x =4,
e.g2 if we had 10 handshakes in all it means
1+2+3+4=10,
so therefore (x-1) = 4, then x = 5.

I know there must be an easier way to this, oga godwin show us the way. This method above took me time to develop.

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Re: Can I Get Answer To This ? by Nobody: 10:42pm On Dec 16, 2016
so just keep adding starting consecutively from 1till you get the total number of handshakes, keeping in mind that the last number is equal to x-1. or simply just add 1 to the last number.

there definitely has to be an easier way, maybe through combination and permutation.

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Re: Can I Get Answer To This ? by Godwin0420(m): 11:37am On Sep 08, 2017
The total number of handshakes= n(n-1)/2 where n is the number of people involved.

I really want godwin0420 to explain how he got the answer. I know for a fact that he is right, you can confirm by solving it backwards.
I also solved it myself but it took me a whole lot of time and I don't know how to explain it well, I sha developed this method and i'm pretty sure it works for all cases though it is a bit cumbersome and lengthy
1+2+...+(x-1) = y,
where x is the number of people in the party and y is the total number of handshakes. assuming the total number of people shaked each other just ones.

so therefore we have, 1+2+3+4+5+6+7+8+9+10+11=66,
from this you can infer that (x-1)=11,
so therefore x = 12,
it works for all cases,
e.g if we had 6 hand shakes in all it means
1+2+3=6,
so therefore (x-1)=3, then x =4,
e.g2 if we had 10 handshakes in all it means
1+2+3+4=10,
so therefore (x-1) = 4, then x = 5.

I know there must be an easier way to this, oga godwin show us the way. This method above took me time to develop.

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