30. Two guests shake hands exactly once with one another. How many handshakes are
exchanged among nine guests?
A.36
B. 42
C. 35
D. 30
Answers
Answered by
0
Answer:
36
Step-by-step explanation:
You have to use Permutations and Combination in this Question.
Use Combination formula because here arrangement is not essential.
Formula: nCr
Solving Put n= 9 r = 2
therefore 9C2 = 9×8/2×1= 72/2=36.
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Answered by
0
Answer:
option A. 36
Step-by-step explanation:
I'll try to explain in simple way:
There are 9 people, each of them exchange hand shakes with the rest.
- Person 1- shakes hands of the rest 8, so x 8
- Person 2- already shaked hand of person 1, so x 7
- Person 3- ... x 6
- ...
- Person 8- has one left only, x 1
- Person 9- has exchanged hand shakes with all at this point, x 0
So total is:
- 8+7+6+5+4+3+2+1=8/2*(8+1)= 4*9=36
Answer is option A. 36
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