There is a leak in the bottom of a cistern. Before the leak it could be filled in 9/2h. It now takes 1/2h longer. If the cistern is full, in how much time would the leakage empty the full cistern?
(a) 45h
(b) 40h
(C) 36h
(d) 56h

• rate of filling before the leakage=1/(9/2)=2/9
  rate of filling after the leakage=1/(9/2+1/2)=1/5
  
  so time required by the leakage to empty the full cistern=2/9-1/5=(10-9)/45
  =1/45=45h
  
  
  
  
• 9 years agoHelpfull: Yes(4) No(0)
• before the leakage the cistern could be filled in 9/2 hour.
  so rate is 2/9 hour.
  after the leakage it takes 9/2+1/2=5 hour.
  now rate is 1/5 hour.
  so the rate of empty of the leakage is 2/9-1/5 hour.
  so it will take 45 hour..
  thats it..
  
• 9 years agoHelpfull: Yes(1) No(0)