Q:

Some litres of acid were drawn off a 54-litre vessel full of acid and an equal amount of water added. Again, the same volume of the mixture was drawn off and replaced by water. As a result, the vessel contained 24 litre of pure acid. How much of the acid was drawn off initially?

• 1
  12 litre
• 2
  16 litre
• 3
  18 litre
• 4
  24 litre