> Here's how you can get exactly 6 liters of water using a 12-liter jug and a 6-liter jug:
1. Fill the 6-liter jug completely.
2. Pour the water from the 6-liter jug into the 12-liter jug. You now have 6 liters in the 12-liter jug.
3. Fill the 6-liter jug completely again.
4. Pour water from the 6-liter jug into the 12-liter jug until the 12-liter jug is full. Since the 12-liter jug already had 6 liters, you will pour 6 liters. This leaves you with 0 liters in the 6 liter jug.
5. Now empty the 12 liter jug.
6. Pour the water from the 6-liter jug into the 12-liter jug.
7. Fill the 6-liter jug completely again.
8. Pour the water from the 6-liter jug into the 12-liter jug until the 12-liter jug is full. Since the 12-liter jug already had 0 liters, you will pour 6 liters. This leaves you with 0 liters in the 6 liter jug.
9. There are 6 liters left in the 6 liter jug.