Q. You have a 3 litre jug and a 5 litre jug.
The jugs have no measurement lines.
How could you measure exactly 4 litre of water using only those two jugs ?
Initially
5 litre jug: 0 litres
3 litre jug: 0 litres
Step1: Fill the 5 litre jug and pour into 3 litre jug.
5 litre jug: 2 litres
3 litre jug: 3 litres
Step2: Empty the 3 litre jug.
5 litre jug: 2 litres
3 litre jug: 0 litres
Step3: Pour remaining 2 litres into 3 litres.
5 litre jug: 0 litres
3 litre jug: 2 litres
Step4: Fill 5 litre jug again.
5 litre jug: 5 litres
3 litre jug: 2 litres
Step5: Pour One litre into 3 litre jug because it has only one litre empty.
5 litre jug: 4 litres
3 litre jug: 3 litres
Finally you have 4 litres of water into the 5 litre of jug.