From a cask of wine, containing 64 liters, 8 liters are drawn out and the cask is filled up with water. If the same process is repeated a second, then a third time, what will be the number of liters of wine left in the cask?

• 42 1 kg 8
• 42 3 kg 8
• 48 7 kg 8
• 42 7 kg 8