A cistern has a leak which would empty it in 12 hours. A tap is turned on which adds 20 liters a minute into the cistern and it is now emptied in 20 hours. How many liters does the cistern hold?

32000 35000 36000 38000

36000

B's efficiency = 5 - 3 = 2 l/h B fills the tank in = \(\frac{60}{2}\) × 60 = 1800 minutes Total capacity of tank = 1800 × 20 = 36000 ltr.