48 persons P1, P2, P3,……. P48 met and shook hands in a circular fashion i.e. a total of 48 handshakes among the pairs (P1, P2), (P2, P3), (P3, P4), ……..(P46, P47), (P47, P48) and (P48, P1). Find the least value of N for which a group of N persons can be formed such that each of the remaining persons outside the group shook hands with at least one person in the group.

• Answer is 16..
  As P2 shook hands with P1 & P3.. similarly P5 shook hands with P4 & P6... so on till.. P48..
  this gives us series..
  2,5,8,11,....48 as an A.P. with n=16
• 10 years agoHelpfull: Yes(15) No(1)
• from this arrangement,the pair(p1,p2),(p2,p3),(p3,p4),.....(p46,p47),(p47,p48)and(p48,p1).If we seperate p3,p6,p9......p48.The total 16 person the remaining person must read have shaked hand with atleast one person.so,
  Ans=16
  
• 10 years agoHelpfull: Yes(14) No(5)
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• @namrata kumari could u explain this well ? pls ,how u seperte p3,p6,p9......p48
• 10 years agoHelpfull: Yes(0) No(1)
• please explain your solutions. @namrata and @shubham
• 10 years agoHelpfull: Yes(0) No(0)
• @vignesh & nisha--- p2 is shaked hands with p1 & p3, p5 shaked hands with p4 & p6
  
  i think shubam took a diff 2 and 5 ie 3 and went on adding for previous value ie 2+3=5,5+3=8,8+3=11,14,17,20,23,27,30,33,36,39,42,45,48 total="16"
• 10 years agoHelpfull: Yes(0) No(0)
• new series will be 2,5,8,11 ....48
  then tn=a+(n-1)d
  48 =2+(n-1)3
  solve ull get 16.. something .. ans is 16 neglect the decimals ..
• 9 years agoHelpfull: Yes(0) No(0)