The Milkman Is At The Door

He can fill 3 liter, then dump the 3 liters into the 5 liter. He'll fill the 3 liter again, and dump it again into the 5. Since it is 6 liters, he will fill the 5 liter completely and have 1 liter left in the 3. He pours the 5 back into the 8, and puts the 1 from the 3 into the 5.

This leaves him with 1 liter in the 5, and 7 in the 8. All he need do now is pour the 7 into the 3. Once the three is full, he will be left with 4 liters in the 8 liter jug.

Use 3 liter jar to fill 5 liter jar twice. in second attempt 1 liter will be left in 3 liters jar. empty the five liter jar and put that 1 liter milk into 5 liter jar again pour three liters of milk in already 1 liter containing jar (5ltr) using 3 liter jar and there u are its 4 liter :)

The milkman has 8L of milk in the 8 litre jar initially which gives us the following configuration : - j8 j5 j3 - 8L 0L 0L
The following allows him to have 4L of milk in the 5 litre jar - 3L 5L 0L - 3L 2L 3L - 6L 0L 2L - 1L 5L 2L - 1L 4L 3L

Stating the litres in the jars as [8, 0, 0] which shows litres of milk in 8 litre, 5 litre and 3 litre jars respectively. ->Fill 5 litre jar from 8 litre jar. New state - [3, 5, 0] ->Fill 3 litre jar from 5 litre jar. New state - [3, 2, 3] ->Empty the 3 litre jar into the 8 litre jar. New state - [6, 2, 0] ->Empty the 2 litres from the 5 litre jar into 3 litre jar. New state - [6, 0, 2] ->Fill 5 litre jar from the 6 litres in 8 litre jar. New state - [1, 5, 2] ->Fill the 3 litre jar from the 5 litre jar. 1 litre is required. New state - [1, 4, 3] We have 4 litres in the 5 litre jar.

Just fill 3L jar and 5L jar .Then pour down half from each filled jar tothe empty 8L jar.you will get 4L.

A more faster way is to fill 3 liter in 5 liter bottle and mark the level.Then fill it to its full from the 8 liter bottle which will have 5 liters now as 3 liters are already taken.Now drain out milk upto that mark from 5 liter bottle. Then do it again and you will get your 4 liter.