I was watching this move, revenge to the death or something.

They had to stop a bomb from blowing up. To disarm it they had to place exactly 4 liters of water on this measuring device.

There was a water fountain near them and they had 2 jugs, A 5 L and a 3 L jug.

So you gotta fill exactly 4 L and put it on the weight scale, how do you do it?

An you cannot estimate with your eye. For example, you can't fill the 3 L jug, dump it into the 5 Liter and then fill the 3 L jug 1/3 of the way and then pour it into the 5 L jug to get 4 L. It has to be exactly 4 L on the dot. How do you do it?

Originally posted by Suzianne 1. Fill the 3L jug and pour it into the 5L jug.

2. Fill the 3L jug again, and pour it into the 5L jug until the 5L jug is full. 1L remains in the 3L jug.

3. Empty the 5L jug.

4. Pour the 1L from the 3L jug to the 5L jug.

5. Fill the 3L jug and pour it into the 5L jug.

6. et voila! 4L is now in the 5L jug.

Better this way:

(1) Fill the 5L jug
(2) Pour inte to 3L jug. Now you have 2L in the 5L jug, right?
(3) Pour the 2L from the 5L jug into the measuring device. And the half job is done.

(4) Do exactly the same thing again and you will have 4 liters in the measuring device and the bomb is deactivated.

(1) Fill the 5L jug
(2) Pour inte to 3L jug. Now you have 2L in the 5L jug, right?
(3) Pour the 2L from the 5L jug into the measuring device. And the half job is done.

(4) Do exactly the same thing again and you will have 4 liters in the measuring device and the bomb is deactivated.

(1) Fill the 5L jug
(2) Pour inte to 3L jug. Now you have 2L in the 5L jug, right?
(3) Pour the 2L from the 5L jug into the measuring device. And the half job is done.

(4) Do exactly the same thing again and you will have 4 liters in the measuring device and the bomb is deactivated.

That's what first came to my mind but it doesn't work.

You only have 2 jugs, so you can't repeat the pattern again for the second time.

Originally posted by sonhouse What about the weight of the jug?

Weight of the jug is neglible. 4 Liters of waters = 4 Kg = about 10 pounds. A jug's weight would hardly change anything.

Well at least that's how we engineers do it, so the next time you are in a building or driving a car or on a bridge, just rememeber we use this neglible stuff a lot in our practise ðŸ™‚

(1) Fill the 5L jug
(2) Pour inte to 3L jug. Now you have 2L in the 5L jug, right?
(3) Pour the 2L from the 5L jug into the measuring device. And the half job is done.

(4) Do exactly the same thing again and you will have 4 liters in the measuring device and the bomb is deactivated.

This is what you have to do if you start with the 5L jug.

1. Fill the 5L jug
2. Pour into the 3
3. Pour the 2 from the 5L jug into the 3L jug
4. Fill the 5L jug
5. Pour from the 5L into the 3L ... leaves 4L in the 5L jug

Originally posted by FabianFnas Why not just pour water into the deactivating devise until you hear the deaktivating click, then you stop pour? Problem solved!

If I'm wrong, don't be concerned.
This death is very quick, you won't feel a thing.

You really have to read things.

The bomb will go off as soon as there is a weight on it other than 4 L.

This means you hav eto put the 4L on the device in one go.