Hercules goes to fight Hydra,the monster that currently has 200 heads.However,every time hercules kills some of hydra's heads the remaining heads double in number.So,if hercules kills one head right now,the number of heads will become 1999*2=3998.In order to fight the hydra,Hercules decides to double the number of arrows he has got each timehe kills hydra's heads.Presently,he has only one arrow and a single arrow can kill only one head of hydra.If hercules starts attacking the hydra once every minute and if everytime he attacks he uses all the arrows that he has,after how many minutes will he be able to finish all of hydra's heads?
(a)4000 mins
(b)2000 mins
(c)1999 mins
(d)hercules should give up hope of killing the hydra

• None of these options will acceptable for 200heads.
  Answer as per question is 200minutes.
  
  
  But If it is 2000 heads means,answer is
  b)2000 mins.
  
  Heads after 1st minute = 1999*2 = 3998 = (2000-1) *2
  Heads after 2nd minute = 3996*2 = 7992 = (2000-2) *2^2
  Heads after 3rd minute = 7988*2 =15976 = (2000-3) *2^3 and so on..
  
  Thus after nth minute,number of heads = (2000-n)*2^n
  
  So,if all the heads are killed,the above expression will become zero at the nth minute.
  By putting n=2000, expression would be 0.
  
  So, answer is Option b)2000minutes.
• 11 years agoHelpfull: Yes(2) No(0)
• Pls read first line as
  
  Hercules goes to fight Hydra,the monster that currently has 2000 heads.
• 11 years agoHelpfull: Yes(0) No(0)
• 2000 mins is correct.
• 11 years agoHelpfull: Yes(0) No(0)