Filling water jugs

Question

You have three jugs with volumes of 12, 8, and 5 liters. The 12L jug is full of water, while the other two jugs are empty. You have no other source of water.

Using these jugs, how can you obtain exactly 6 liters of water in the 12L jug?

I've tried a lot of things but can't seem to know what to do — Cassey, Sep 01 '17 at 09:35
Hello and welcome to Puzzling. I've edited your question slightly for clarity. Please feel free to edit it further or to roll back my changes. — Lawrence, Sep 01 '17 at 11:08
This is confusingly written. You mix units (inches or liters? Pick one!) and it seems likely that your intention is that the 12 jug is full and there is no other source of water, but it doesn't say that - if that's what you intend, please edit the puzzle so that is clear. — Rubio, Sep 01 '17 at 11:28
Possible duplicate of A general solution to the decanting problem? (aka jug-pouring, water-pouring) — Rand al'Thor, Sep 01 '17 at 12:04

score 8 · Answer 1 · edited Jun 17 '20 at 08:22

8

Answer

12j-12, 8j-0, 5j-0
12j-4, 8j-8, 5j-0
12j-4, 8j-3, 5j-5
12j-9, 8j-3, 5j-0
12j-9, 8j-0, 5j-3
12j-1, 8j-8, 5j-3
12j-1, 8j-6, 5j-5
12j-6, 8j-6, 5j-0 (done!)

Ends up with 6 inches of water in the 12-inch jug with no water wasted!

edited Jun 17 '20 at 08:22

Community

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answered Sep 01 '17 at 11:43

Gunnar Södergren

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After step 6, you could fill 5 from 8, then pour 5 into 12 to not waste anything. – Apep Sep 01 '17 at 11:52
Right, that's even better. I'll update my answer, thank you! – Gunnar Södergren Sep 01 '17 at 11:53
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This is the only way to perform the task in seven transfers, and it is not possible with less. – Jonathan Allan Sep 06 '17 at 19:53

Lawrence · Answer 2 · 2023-12-21T15:20:44.387

4

Fill the 8L jug from the 12L jug, then fill the 5L jug from the 8L jug. This leaves 3L in the 8L jug. Discard that 3L. Empty the 5L jug into the 12L jug. Repeat.

This discards 6L and leaves 6L in the 12L jug.

edited Dec 21 '23 at 15:20

answered Sep 01 '17 at 11:12

Lawrence

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If poring-with spilling counts as one step, then you can simplify this solution to 6 steps. – Kris Van Bael Dec 22 '23 at 08:42

score 1 · Answer 3 · edited Sep 06 '17 at 19:40

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here is another way of doing this:

12j-12, 8j-0, 5j-0
12j-0, 8j-8, 5j-4
12j-8, 8j-4, 5j-0
12j-3, 8j-4, 5j-5
12j-3, 8j-8, 5j-1
12j-11, 8j-1, 5j-0
12j-6, 8j-1, 5j-5(Done!)

edited Sep 06 '17 at 19:40

MMAdams

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answered Sep 06 '17 at 19:10

Mohit Tyagi

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I don't know how to hide the text, but these steps are correct to get the 6L in 12L jug – Mohit Tyagi Sep 06 '17 at 19:22
It's another way yes, but do note that this takes nine transfers rather than the (minimal) seven (even though it was not asked of us to be optimal in transfers). – Jonathan Allan Sep 06 '17 at 19:52

Filling water jugs

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