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

• Its 3. Consider set as (a1,a2,a3). Now possible handshakes are (a1,a2),(a2,a3),(a3,a1). Now see that every person shakes hands with every other person. If set is 4 this is not possible. So ans is 3.
• 12 years agoHelpfull: Yes(22) No(8)
• here answer is 4. the set comprises host,hostress,any two other guests.
• 12 years agoHelpfull: Yes(5) No(2)
• A set have 3 people,in circular 58 hand shake means 24 people, set have 3 people means possible is 4!=24. so answer is 3
• 12 years agoHelpfull: Yes(2) No(7)