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

• at most 4
  host, hostess, a pair from circular fashion
• 11 years agoHelpfull: Yes(2) No(5)
• ans is 3 .
  
• 11 years agoHelpfull: Yes(1) No(4)
• it shld be 3
• 11 years agoHelpfull: Yes(0) No(5)
• let a1 be the part of the set.
  than a1 will shake hand with a2 and the host and hostess.
  also the host will shake hand with hostess.
  so in one set s there are 4 people shakin hands.
• 11 years agoHelpfull: Yes(0) No(2)