19 people (a1, a2, ..... , a19) are invited to a party. The host and the hostess shake hands with each invitee and also with each other. The invitees shake hands in a circular fashion, i.e. the pairs (a1, a2), (a2, a3), ....,(a18, a19),(a19, a1) shake hands. So, in all there are 58 handshakes. Let S be a set of people such that every pair in S shake hands. The size of S is at most
option
a) 2
b) 3
c) 1
d) 4

• answer is 2,because out of 58 we would remove host handshake between them 58-1=57,and each host make 19 hand shake with each guest 19*2=38 now 57-38=19 now if we group( a1,a2),(a2,a3).........(a19,a1),there wud be 19 handshake so atmost there were 2 ppl in the each group.if we make a gorup of three then there are only 10 handshake in cycles.
• 11 years agoHelpfull: Yes(7) No(1)
• 4.... any pair of host and hostess
  
• 11 years agoHelpfull: Yes(5) No(6)
• answer is 2
• 11 years agoHelpfull: Yes(2) No(0)
• plz explain in detaill.....
• 11 years agoHelpfull: Yes(0) No(0)
• plz explain clearly how it is 4?
• 11 years agoHelpfull: Yes(0) No(0)
• pls explain in detail.
• 11 years agoHelpfull: Yes(0) No(0)
• there can be atmost two hands required to make one handshake and hence the size of s is atmost 2
• 11 years agoHelpfull: Yes(0) No(1)
• I have heard 2 !!! :p
• 11 years agoHelpfull: Yes(0) No(0)