Water jug problem solved with online simulator.
1) Fill up Jug A with 5 litres and Fill jug B from A – there are 2 litres left in Jug A.
2) Empty Jug B and then tip the remaining 2 litres from Jug A into Jug B.
3) Re-Fill Jug A with 5 litres and then fill Jug B again from it. As Jug B already has 2 litres in it, only 1 litre is taken out of Jug A. i.e. Jug A now has 4 litres left in it.
To get 2 litres….
Fill Jug A and Fill Jug B from Jug A. You have 2 litres in Jug A left.
To get 1 litre….
Fill Jug A and Fill Jug B from it. Now empty Jug B and pour remaining 2 litres from A into B.
Fill Up Jug A again and tip the rest into Jug B, we now have 4 litres in Jug A.
Empty Jug B and Fill again from Jug A, A has 4 litres, 3 litres of which will fill up Jug B, you now have 1 litre remaining in Jug A.
Simple really!!
For a live try visit here