A secret can be told only 2 persons in 5 minutes .the same person tells to 2 more persons and so on . How long will take to tell it to 768 persons ?

• one person telling to 2 that means he takes 2.5 min to 1 person....
  
  
  now, 1 is telling to another 2 this two telling another 2 person and so on....
  
  that means chain is 1 to 2, 2to 4, 4to 8, 8 to 16...
  
  means 2 48 16....512.
  upto this this will take 45 min now these person means 256 telling only 1 the total person willbe 768 & 45 + 2.5 = 47.5 min
• 10 years agoHelpfull: Yes(27) No(5)
• 40 minutes
  proof:
  in first 5 min 1 person tells to 2 other people , in the next 5 min 2+1 tell to 6 other people , in the next 5 min 6+2+1 tell to 18 new people n in the next 5 min 18+6+2+1 tell to 27*2 new people n so on
• 13 years agoHelpfull: Yes(6) No(9)
• 2^x = 768
  
  x = log(768) / log(2)
  
  x = 9.5849
  
  Then times that by the doubling time = 5 minutes
  
  9.5849 * 5 = 47.9245 minutes = 47 minutes, 55.47 seconds
  
• 11 years agoHelpfull: Yes(6) No(1)
• Ans is 50 min.
  1->2->4->8->16......->512->1024
  2^9=512 After this definitely one person need 5 min to tell to others. So totally 10 * 5 min =50 min
• 13 years agoHelpfull: Yes(5) No(10)
• 2^8 x 3 = 768
  to tell the secret to 2^1 persons it takes 5(5 x 1) minutes
  to tell the secret to 2^8 persons it takes 40(5 x 8) minutes
  then there will be remaining 3 persons who can be split as (2 + 1) persons
  so obviously the time for (2 + 1) persons will be (5 + 2.5) minutes which will be 7.5 minutes
  so total 2^8 x 3 (768) persons it will take (40 + 7.5)= 47.5 minutes
• 6 years agoHelpfull: Yes(2) No(0)
• 768*5/2 = 1920
• 13 years agoHelpfull: Yes(1) No(13)
• The ans is exactly 45min. person
  5-> 1+2=3
  5->3*2=6
  5->6*2=12
  5->12*2=24
  5->24*2=48
  5->48*2=96
  5->96*2=192
  5->192*2=384
  5->384*2=768, so this is the correct answer thing logically. exactly at the 45th minutes the truth will pass to 768 persons
• 9 years agoHelpfull: Yes(1) No(0)
• 384*5 minutes=1920 minutes
• 13 years agoHelpfull: Yes(0) No(14)