A leaky cistern is filled in 5 hours with 30 pairs of 12 litres each, but in 3 hours with 20 pails of 16 litres each, the pails being poured in at intervals. Find how much the cistern hold?

• ans : 260
  explaination:
  in 5hrs water filled in leaky cistern= 30*12=360
  in 3hrs water filled in leaky cistern= 20*16=320
  now supposse water leaks from cistern at the rate of x ltrs/hrs
  so water leaks in 5 hrs =5x and in 3hrs=3x
  now quantity of water in cistern remains same in both cases.
  so water in cistern after 5 hrs= 360-5x
  and in 3hrs= 320-3x
  360-5x=320-3x
  solving x=20
  so quantity of cistern will be 360-5x=360-5*20=260.
• 10 years agoHelpfull: Yes(50) No(1)
• just a small thought
  1 - 30 *12 =360 lit but it is 5 hrs
  2 - 20 * 16 = 320 lit but it is in 3 hrs
  so let us assume the capcity of cristern is x < 320
  the diff bw 1 and 2 is 2 hrs and 40 lit
  so the leak in cristern with the rate of 1 hr for 20 lit
  so for 5 hr it is 100 lit
  so 360-100=260 lit dudesssss
• 10 years agoHelpfull: Yes(8) No(4)
• ans=240 liters.
  in 3hr filled=3*(2*30)*12=2160 liters
  and poured in 3hr=3*(2*20)*16=1920 liters
  so cisten hold=2160-1920=240 liters
  so ans=240 liters.
• 10 years agoHelpfull: Yes(2) No(6)
• Let Y lts be drained per hour through leakage
  then 30*12 - 5Y = 20*16 - 3Y (Capacity of the cistern)
  360 - 5Y = 320 - 3Y
  360-320 = 5Y - 3Y
  2Y = 40
  Y= 20 lts
  i.e 360 - 5(20) = 360 - 100= 260 Lts.
• 9 years agoHelpfull: Yes(1) No(0)
• 2160-1920=240 liters
• 10 years agoHelpfull: Yes(0) No(0)