In a village, there are
N
wives who know each other. All of them know a rumor. If one calls another one over the telephone, they can share every rumor they know. At least how many calls are necessary to get every wife to know every rumor??

• At lest
  
  N-1 +N-2 = 2N-3 calls are to be made.
  
  First lady will call all other (N-1) ladies.
  
  Then again she will call (N-2) ladies excluding the last one.
• 12 years agoHelpfull: Yes(2) No(1)
• Minimum N(N-1)/2 combinations required to have a reach.
• 12 years agoHelpfull: Yes(2) No(2)
• @ Davendra,
  Pls check.
  If there are 4 ladies.
  First lady will make call to 3 ladies one by one and tell all the rumours she know by that time.During 3rd call , 4th lady and first lady have got details of all 4 rumours. Then First lady will only make 2 more calls to 2nd and 3rd lady and then every lady will know every rumour.
  so 5 calls are sufficient.
  But as per your answer,
  min 4*3/2 =6 calls are reqd which may not be correct.
  Pls check.
• 12 years agoHelpfull: Yes(2) No(1)
• if ther r 4 wives then 4 calls are needed.when 1st nd 2nd wives r talkng at the same time 3rd nd 4th wives r also talking.after that when 2nd nd 3rd wives r talkng then 1st nd 4th wives r talkng at the same time.thus nly 4 calls r needed at least to get the rumors amongst them 4.
• 12 years agoHelpfull: Yes(0) No(0)