7 people meet and shake hands with one another, how many
handshakes occur?
Answers were Sorted based on User's Feedback
21 is correct
suppose 1,2,3,4,5,6,7 people.
1st one(tillu) shakes hand with all other 6 members.
then 2nd one(bunty) with 5 people only,since already he
shook hand with tillu.
then 3rd one with 4 people only.(with tillu &bunty its
over)
so 6+5+4+3+2+1=21
(7th one need not do it. already every one shook hand with
him,so not counted him)
| Is This Answer Correct ? | 53 Yes | 4 No |
Answer / pradip
ok boys the answer is 21
let the friends be A,B,C,D,E,F,G
FIRSTLY, SECONDLY, THIRDLY, FOURTHLY, FIFTHLY, SIXTHLY,
A-B]1 B-C]7 C-D]12 D-E]16 E-F]19 F-G]21
A-C]2 B-D]8 C-E]13 D-F]17 E-G]20
A-D]3 B-E]9 C-F]14 D-G]18
A-E]4 B-F]10 C-G]15
A-F]5 B-G]11
A-G]6
===============21 TIMES
LASTLY,
G-HAS ALREADY DONE WITH EVERYBODY.......
| Is This Answer Correct ? | 32 Yes | 3 No |
Answer / frulog
Immanuel is correct ...
21 times
12
13
14
15
16
17
23
24
25
26
27
34
35
36
37
45
46
47
56
57
67
| Is This Answer Correct ? | 28 Yes | 4 No |
Answer / eric
correct answer is 21.
Srinivas is the foolest gye I have ever seen. Such fool
guys should not be allowed to post their bloody answers.
| Is This Answer Correct ? | 23 Yes | 2 No |
Answer / sahas
7 people ... U need two people for one handshake.
Using nCr Combination formula = n! / { (n-r)!r! }
i.e, 7C2 = 7! / {(7-2)! 2!}
= 7*6*5*4*3*2*1 / {(5*4*3*2*1)*(2*1)}
= 7*6 /{(2*1)}
=21
| Is This Answer Correct ? | 16 Yes | 1 No |
Answer / raj
in he 7 peoples
1st person shakes remaing 6
2nd '' '' '' 5
3rd '' '' '' 4
4th '' '' '' 3
5th '' '' '' 2
6th '' '' '' 1
7th '' '' '' 0
total--------------------21
| Is This Answer Correct ? | 14 Yes | 0 No |
Answer / auswin
An alternate mathematical approach:
If 'n' people shake hand with each other, the first
person can shake hands with 'n-1' people, the second with
'n-2' people and so on till the last person with 'n-n i.e 0'
people.
So, the total number of handshakes are
n-1+n-2+n-3+....n-n which is nothing but n*n-(1+2+3+....n)
which is equal to
n^2 -(n(n+1)/2) = (2n^2-n^2-n)/2 = (n^2-n)/2 = n(n-1)/2 ..!!
Hence, the number of handshakes possible with n people is
n(n-1)/2......
| Is This Answer Correct ? | 8 Yes | 1 No |
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