It takes five minutes to pass a rumour from one person to two other persons. The tree of rumour continues. Find how many minutes does it take spread the rumour to 768 persons.

• After 5 mins ..... 3 persons will get rumour
  After 10 mins .... 3*2+3= 9 persons will get
  after 15 =5*3 min ......9*2+9 =27 = 3^3 persons will get news.
  ...
  .....
  after 5*6 mins ... 3^6 = 729 persons will get news
  after 5*7 = 35 mins .... 3^7 persons will get news which will cover more than 768 persons.
  
  
  so 35 mins.
  or
  As It takes five minutes to pass a rumour from one person to two other persons.
  and It takes 2.5 minutes to pass a rumour from one person to one other person.
  if proportional time is allowed, 30+2.5 = 32.5 mins.
• 12 years agoHelpfull: Yes(3) No(2)
• 47.5 min
  
  5*9+2.5=47.5
• 12 years agoHelpfull: Yes(2) No(2)
• Mr. Pargat pal singh ji.. Please don't give wrong solutions
• 10 years agoHelpfull: Yes(1) No(1)
• 15min (reslly fast isnt it!!!!!)
• 12 years agoHelpfull: Yes(0) No(2)
• 74.5m .......
• 12 years agoHelpfull: Yes(0) No(2)
• It will take 45 minutes to spread rumor to 768 persons.
  Rumor will spread as :
  (Initiator of rumor)1->2^1->2^2->2^3->2^4->2^5->2^6->2^7->2^8->2^9
  The rumor will have to pass through 9 phases so it will take 45 (9*5) minutes.
  
• 12 years agoHelpfull: Yes(0) No(2)