Water From 3 Jugs Into Two Pools
Logic puzzles require you to think. You will have to be logical in your reasoning.
You have:
 two 10liter jugs, full of water
 one 9liter jug, empty
 two large pools, empty
Your objective is to end up having 4 liters of water in each pool, and one liter of water in the 9liter jug.
You have nothing else at your disposal and you can not measure using eye or shape of jugs. You can not pour water from pools, only into them.
HintThis needs 29 steps to fill two pools with 4liters, and an additional 4 steps to get 1 liter in the 9liter jug, for a total of 33 steps.
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Answer
Label the 10liter jugs as A and B, the 9liter jug as C, and the two pools as Pa and Pb. The problem can be solved in 33 steps, as shown below. Each step is shown in one row, starting with the step number, followed by the jug we poured water from, then the quantity of water, then the jug/pool we poured water into... i.e. A >( 1)> Pb means we poured 1 liter of water from jug A (being 1st 10liter jug) to pool Pb (being 2nd pool). Finally in the row we show how much water we have in each jug/pool after performing this step.

#: From > Qty > To = A B C Pa Pb

0: _____________ = 10 10 0 0 0
1: A >( 9)> C = 1 10 9 0 0
2: A >( 1)> Pa = 0 10 9 1 0
3: C >( 9)> A = 9 10 0 1 0
4: B >( 9)> C = 9 1 9 1 0
5: B >( 1)> Pa = 9 0 9 2 0
6: C >( 1)> A = 10 0 8 2 0
7: C >( 8)> B = 10 8 0 2 0
8: A >( 9)> C = 1 8 9 2 0
9: A >( 1)> Pa = 0 8 9 3 0
10: C >( 9)> A = 9 8 0 3 0
11: A >( 2)> B = 7 10 0 3 0
12: B >( 9)> C = 7 1 9 3 0
13: B >( 1)> Pa = 7 0 9 4 0
14: C >( 3)> A = 10 0 6 4 0
15: C >( 6)> B = 10 6 0 4 0
16: A >( 9)> C = 1 6 9 4 0
17: A >( 1)> Pb = 0 6 9 4 1
18: C >( 9)> A = 9 6 0 4 1
19: A >( 4)> B = 5 10 0 4 1
20: B >( 9)> C = 5 1 9 4 1
21: B >( 1)> Pb = 5 0 9 4 2
22: C >( 5)> A = 10 0 4 4 2
23: C >( 4)> B = 10 4 0 4 2
24: A >( 9)> C = 1 4 9 4 2
25: A >( 1)> Pb = 0 4 9 4 3
26: C >( 9)> A = 9 4 0 4 3
27: A >( 6)> B = 3 10 0 4 3
28: B >( 9)> C = 3 1 9 4 3
29: B >( 1)> Pb = 3 0 9 4 4
30: C >( 7)> A = 10 0 2 4 4
31: C >( 2)> B = 10 2 0 4 4
32: A >( 9)> C = 1 2 9 4 4
33: C >( 8)> B = 1 10 1 4 4
After the 33rd step we end up with 4 liters in each pool (Pa and Pb), and 1 liter in the 9liter jug (C), as requested in the problem.
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Comments
razor188
Oct 04, 2004
 oldy but a goody 
I_am_the_Omega
Oct 14, 2004
 I think I got the answer but I haven't got a clue from the explanation. You keep adding water 1L at a time, filling the 10L to the top with the other 10L bottle, and using the full 10L to put in the 9L, right? 
Smart_ASS
Oct 15, 2004
 I used to play i game like this in grade school, but a little less advanced, this one was esay and iu accually completed it in 30STEPS not 33, and up with 4L in pA and pB, 3L in A, 0L in B, and 9L in C.(20L). After leveling it off the first time with 2steps, repetively transfer the 9L in C to B and add 1L from A to B, add 9L from B to C, put remaining 1L in B in pA.(you will do this 7 times[7x4steps = 28+2steps =30 STEPS]). THE GAME I PLAYED IN GRAMMER SCHOOL WAS TO SEE WHO DID IN IN THE LEAST AMOUNT OF STEPS, SO LOOKS LIKE I WON 
nenad
Jun 24, 2005
 I think that solution under 33 moves for this problem does not exists, Smart . I assume you were reffering to another problem, one where target is to end up with 9L in jug C. Actually, that one can be solved in 29 moves 
grace317
Apr 22, 2015
 Tedious but fun! Can't believe I actually went through all 33 steps. Wrote my answer in a way I found clearer to read though. 
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