The 8 litre one is full of water. By pouring water 4 times from one to another how can one bucket end up with exactly 4 litres in it?? This is driving me nuts..
Call the 8L, 5L and 3L buckets A, B and C respectively.
so - pour A into B
then B into C
then pour C into A
and B into C
then A into B
and B into C leaving 4L in B
Brilliant - I kept on stopping when I got to the 4th pour. It was a test set by pengiun books re the Malice Box Quest. Maybe you should have a bash http://www.maliceboxquest.com.
In 4 moves... 1st get a pair of old-fashioned scales!
Weigh the empty 5L and keep the counterbalance weights for later.
Fill the 5L & 3L from the 8L bucket (2 moves)
Now weigh the empty 8L as per the 5L.
Empty 3L into the 8L (3rd move).
Set the scales up with 5L + the 8L counterweight on one side, and 8L + 5L counterweight the other side.
Carefully pour from the 5L into the 8L until they balance (4th move).
I know people will say that every time you pick up the 5L to pour and put it back to check the balance is a move.
But definition of "pour" from Chambers is "to flow or cause something to flow in a downward stream", so a syphon could be used to do the pouring in 1 go.
Yes/No/not convinced? Put it this way - I can't think of a better answer!!! :o) ;o)