in a room with 10 people, everyone shakes hands with everybody else exactly once. how many hand shake are their?
please put answer and explanations below thankyou
please put answer and explanations below thankyou
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Answer:
45 handshakes
Step-by-step explanation:
use the combination formula: Cn = n!/[r!(n-r)!]
there are 10 people. so n=10
and in a handshake, there are 2 people at a time involved. r=2
substituting:
C10 = 10!/[2!(10-2)!] = 10!/(2!×8!) = 45
therefore, there are 45 handshakes