Question

There are 3 beakers of 3,5 and 8 litres each. first 2 are empty and last is full. how to pour exactly 4 litre into one of the beaker?

Answer 1

                    3L beaker..... 5L beaker..... 8L beaker

Initially:          0---------------0-------------------8
Step 1            0---------------5-------------------3
Step 2            3---------------2-------------------3
Step 3            0---------------2--------------------6
Step 4            2---------------0--------------------6
Step 5            2---------------5--------------------1
Step 6            3---------------4--------------------1

Illustration:
initially: 3L empty... 5L empty...8L FULL
Step 1: From 8L beaker fill the 5L beaker..Now 5L full..8L has 3Litres
Step 2: From 5L beaker, fill the 3L..Now 3L full,.. 5L has 2Litres..8L has 3L
Step 3:Pour the 3L content into 8L..Now 3L empty...5L has 2L and 8L has 6L
Step 4: Pour the 5L ocntent into 3L...Now 3L has 2Litres.. 5L empty.. 8L has 6Litres..
Step 5 : Pour 8L content into 5L beak.... 3L has 2L...5L FULL...8L has 1L
Step 6: Pour the contents from 5L into 3L beak...Since 3L needs only 1 more liter to make it full..3L full(3L).....5L(5-1=4L)...8L has 1 litre...
Hence, exactly 1 beaker has 4 litres.
Hope it helps.