There are 2 solutions to this...

Solution 1 :

1) First, fill the 3L bottle and pour 3 litres into the 5L bottle.

2) Again fill the 3L bottle. Now pour 2 litres into the 5L bottle until it becomes full.

3) Now empty the 5L bottle.

4) Pour the remaining 1 litre from the 3L bottle into the 5L bottle.

5) Now again fill the 3L bottle and pour the 3 litres into the 5L bottle; now you have 4 litres in the 5L bottle!

Solution 2 :

1) First, fill the 5L bottle and pour 3 litres into the 3L bottle.

2) Empty the 3L bottle.

3) Pour the remaining 2 litres in the 5L bottle into the 3L bottle.

4) Again fill the 5L bottle and pour 1 litre into the 3L bottle until it becomes full; Now you have 4 litres in the 5L bottle!


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