N people were in a party and were seated in a circular manner. If each of the two present in the party, except the pairs that were adjacent,sang a song and If a song lasted for 2 mins and 28 mins was taken for singing the songs, find N.

• N = 7
  
  Each song = 2 min
  Total time = 28 min
  => No of songs sung = 14
  
  NC2 - N = 14
  N(N-1)/2 - N = 14
  
  => N = 7
• 11 years agoHelpfull: Yes(32) No(11)
• N =no.of people
  when they are made as pairs,N/2 people will be there when they are made as pairs .
  half of N/2 will be singing the song since pairs adjacent to each other will not sing the song ...
  Each song = 2 min
  Total time = 28 min
  => No of songs sung = 14
  N/4=14
  N=14*4
  N=56
• 11 years agoHelpfull: Yes(8) No(3)
• a point is mentioned as "except the pairs that were adjacent" so the number of pairs singing the song equals the number of pairs not singing.
  Therefore, No. of non-adjacent pairs singing the song for 28 mins = 14
  => No. of other pairs = 13
  Now, value of N = (14*2)+(13*2) = 54.
• 11 years agoHelpfull: Yes(4) No(1)
• please any thing wrong means correct me . i think the answer is 14 .because adjacent people singing song .so example in a party 5 members means only 5 songs will be happen .so 14 songs means 14 members only in the party .
• 11 years agoHelpfull: Yes(1) No(2)
• ans 14 1-2 ,2-3 b,3-4,4-5,5-6,6-7,7-1 are in a circular manner...so to avoid adjacent pair..
  we can have 1-3,3-5,5-7,2-4,4-6,7-2,and 6-1 by leaving one people in between them 7 nonad pair
  by leaving two people in between them 1-4,2-5,3-6,4-7,5-1,6-2,7-3 we have another 7 non adjacent pair total =7+7=14
  to understand easily draw in circular form and number it and join the numbers as show above
  
• 11 years agoHelpfull: Yes(0) No(0)
• In that problem they clearly said "except the pairs that were adjacent" and they didn't mention any order of seating ,so the pair which singing song should sitting in the opposite of each other.Then every one in the party can able to sang the song and N=28..
• 10 years agoHelpfull: Yes(0) No(0)
• N =no.of people
  when they are made as pairs,N/2 people will be there when they are made as pairs .
  half of N/2 will be singing the song since pairs adjacent to each other will not sing the song ...
  Each song = 2 min
  Total time = 28 min
  => No of songs sung = 14
  N/4=14
  N=14*4
  N=56
• 9 years agoHelpfull: Yes(0) No(0)
• N=7
  
  since it is circular , let us assume ppl in party for a polygon ,
  eg :- like in 4 ppl it forms a sq / rectangle ..
  
  now in order to select no of songs 2 person have sang a song whom are adjacent = diagonal of polygon .
  
  therefore, we know that formula in a diagonal = (n)(n-3)/2
  
  here , (n)(n-3)/2 = 28/2 ---> n = 7 , -4 ( rejected case)
  
  hence , N = 7 :))
  
• 9 years agoHelpfull: Yes(0) No(0)