Pour full bucket of 4 ltrs into bucket of 5 ltr.
Then refill 4ltr and again empty into 5ltr bucket ..
so 5 ltr bucket full and 4 litre bucket has 3 ltrs full.
Empty 5 ltr and then empty the 3ltrs into the 5 ltr bucket.
Again fill 4ltrs and refill the 5ltr bucket .. so balance inthe 4 ltr bucket will remain 2 ltrs.
Then refill 4ltr and again empty into 5ltr bucket ..
so 5 ltr bucket full and 4 litre bucket has 3 ltrs full.
Empty 5 ltr and then empty the 3ltrs into the 5 ltr bucket.
Again fill 4ltrs and refill the 5ltr bucket .. so balance inthe 4 ltr bucket will remain 2 ltrs.