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hi_vis360
November, 2024

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Here is a brain puzzle for all you smarties.

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.David.
Posts: 1273 - Karma: 12
You have 12 diamonds. They all look exactly the same the only way to differenciate them is by weight... there is a fake among them. It weighs differently.
You have a balance. You get to weigh the diamonds 3 times - however you want, and you have to figure out which is the fake.


Jun 15 2006 1:31PM
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ThaLetterM.
Posts: 8609 - Karma: 1,613
weigh 11 of them

divide by 11
weigh the other one
Jun 15 2006 1:32PM
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iskilibertys
Posts: 996 - Karma: 23
hit them all with the scale as hard as you can. the first to break/chip is the fake
Jun 15 2006 1:35PM
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hk_
Posts: 1403 - Karma: 12
I would have done yhe same,actually.
Jun 15 2006 1:36PM
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jonnydub
Posts: 940 - Karma: 10
one by one rub them against eachother, the one that gets scratched is fake
Jun 15 2006 1:38PM
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Chubby.Chaser
Posts: 2926 - Karma: 15
that will only tell you if the "other one" is fake or not

try again
Jun 15 2006 1:38PM
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LDuggan420
Posts: 1611 - Karma: 13
so we dont kno if it weighs more or less?
Jun 15 2006 1:45PM
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scientist
Posts: 6920 - Karma: 348
who the fuck cares. pawn them all
Jun 15 2006 1:46PM
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iskilibertys
Posts: 996 - Karma: 23
you should care, you are a scientist after all.
Jun 15 2006 1:50PM
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LDuggan420
Posts: 1611 - Karma: 13
haha thats what i was thinking
Jun 15 2006 1:52PM
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CJHski
Posts: 2384 - Karma: 126
hmmmm, tell me
NOW
Jun 15 2006 1:54PM
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ThaLetterM.
Posts: 8609 - Karma: 1,613
iiiiiiiiim dumb
Jun 15 2006 2:02PM
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skierdudeguy
Posts: 6574 - Karma: 81
its true you scientifically minded young man.
Jun 15 2006 2:03PM
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chrismoJBEATS
Posts: 5898 - Karma: 44
yeha
Jun 15 2006 2:12PM
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garrett.
Posts: 9304 - Karma: 3,670
bingo
Jun 15 2006 2:13PM
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brizz
Posts: 1051 - Karma: 74
it's a balance
u divide them into 3 groups of 4 and weigh 2 groups if they weigh the same then the fake is in the group not on the balance or it is in the lighter group

take that group and divide it into 2 groups of 2 and weigh again

take the lighter group and divide into 2 groups of 1 and weigh again and the lighter one is the fake then sell it to a mexican
Jun 15 2006 2:15PM
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d-loc
Posts: 7479 - Karma: 15
well i thought of that, but i think the question means u get to weigh then ONLY 3 times. like when you weigh the 4 and then another 4, that is 2 times, u only have 1 more weigh.
Jun 15 2006 2:18PM
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iskilibertys
Posts: 996 - Karma: 23
that's assuming the fake is lighter than the real ones, or a different weight in general, which you cannot assume, because you donotknow tht for sure
Jun 15 2006 2:18PM
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d-loc
Posts: 7479 - Karma: 15
and who said it was lighter, it is just a different weight
Jun 15 2006 2:19PM
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brizz
Posts: 1051 - Karma: 74
it's a balance
you put 4 on one side and 4 on the other and go from there, kinda like a triple beam but with another platform on the other side instead of wieghts
Jun 15 2006 2:23PM
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iskilibertys
Posts: 996 - Karma: 23
my bad, i forgot what the question said...but i still say rely on the diamonds strength
Jun 15 2006 2:25PM
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d-loc
Posts: 7479 - Karma: 15
yeah well then its easy cuz i already thought of that. stupid thread started
Jun 15 2006 2:25PM
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.David.
Posts: 1273 - Karma: 12
Hint: you got the first step correct: divide them into 3 groups of 4. If you weight 2 groups, and they are the same, you know its in the other group you did not weigh.

continue..
Jun 15 2006 2:26PM
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.David.
Posts: 1273 - Karma: 12
The strength has nothing to do with it because we are pretending that they are the same strength.. the only way to figure it out is by weight.
Jun 15 2006 2:27PM
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d-loc
Posts: 7479 - Karma: 15
yeah and brizz that works but you still dont know which one is fake. ur assuming its the lighterr one. but since you dont know this is physically impossible.

if it is heavier, you would pick the light one and have a real diamond.

still think ur close but u dont have it yet
Jun 15 2006 2:27PM
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d-loc
Posts: 7479 - Karma: 15
OH after the 4 n 4... just do 1 n 1, then 1 n 1 to figure out which one is real. DUH
Jun 15 2006 2:29PM
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.David.
Posts: 1273 - Karma: 12
A normal balance.. two platforms on either side with a balance point in the middle. Like the balance on Monty Python when they weigh the woman/witch against the duck, but smaller. :)
Jun 15 2006 2:30PM
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d-loc
Posts: 7479 - Karma: 15
once you do 1 n 1, if they are equal, you keep 1 on and grab another 1. if those are still balanced you know the fake 1 is the remaining one not weighed.
Jun 15 2006 2:30PM
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d-loc
Posts: 7479 - Karma: 15
I WIN
Jun 15 2006 2:31PM
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.David.
Posts: 1273 - Karma: 12
Let's say that when you weigh the first two groups of 4 against each other, they are not equal.. then what?
Jun 15 2006 2:33PM
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d-loc
Posts: 7479 - Karma: 15
you take the 3 groups of 4, weigh the 2 groups of 4 and figure out what group of 4 has the lighter weight.

take that group of 4 and weigh then 1 on 1 with each other.

so right now I have 2 weigh's left

I take 1 on the left, 1 on the right.
if they balance, I take the right side off and grab another 1 from the same group.

if these balance I then know it is the 1 I have not weighed yet.

get it
Jun 15 2006 2:33PM
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d-loc
Posts: 7479 - Karma: 15
then it literally cant be done
Jun 15 2006 2:35PM
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iskilibertys
Posts: 996 - Karma: 23
nope.....?
Jun 15 2006 2:35PM
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.David.
Posts: 1273 - Karma: 12
You can't give up that easily..
Jun 15 2006 2:36PM
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.David.
Posts: 1273 - Karma: 12
I'll check back in a bit.. I'm off to lunch. Keep thinking..
Jun 15 2006 2:38PM
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d-loc
Posts: 7479 - Karma: 15
well im leaving work so im done being on NS today... but i still dont think it can be done.
Jun 15 2006 2:38PM
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sneather
Posts: 6672 - Karma: 19
u switch one group with the one on the table ..... and that will tell u if the fake diamond is heavier or lighter
Jun 15 2006 2:39PM
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danedegruyter
Posts: 2749 - Karma: 1,137
weigh them all once but put them on one at a time and record the mass as it increases, when an UNuniform mass happens it is the fake
Jun 15 2006 2:49PM
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JAYTRON
Posts: 2373 - Karma: 16
or do 6 and 6. take the one with the fake do 3 and 3, take the one with the fake and 1 and 1 with 1 one and if even the one outs fake, or the odd one on balance. that was the easiest puzzle ever
Jun 15 2006 2:54PM
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.David.
Posts: 1273 - Karma: 12
That would take more than 3 times of weighing it out..
Jun 15 2006 2:58PM
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ski_cartel
Posts: 6598 - Karma: 18
no no no you guys are thinking of this all wrong. You get a gun and go the guy who sold you the messed rocks. Then make him tell ou wich one if the fake. Problem solved
Jun 15 2006 3:20PM
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cjgncjgn
Posts: 3023 - Karma: 21
save yourself some time and just take them to a jewler and have him tell you... hehe JEWler... hehe
Jun 15 2006 3:26PM
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Badfish2
Posts: 3453 - Karma: 21
split into 3 groups of 4, and weigh 2 of the groups.
If they are the same, the it's not in that group.

Take 2 from one of the good groups and measure it against 2 of the bad pile.

If those are the same, take one of them and measure it against one of the 2 remaining diamonds...

That's 3 times if it works out that way.
Jun 15 2006 3:31PM
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Badfish2
Posts: 3453 - Karma: 21
If they're the same, the lone diamond is fake, if they're different, then it's the one you're measuring.
Jun 15 2006 3:33PM
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OpIvy
Posts: 741 - Karma: 9
won't work,what if the first measurement they are different? Then you have to waste a weigh determining which is the good and which is the fake.
Jun 15 2006 3:36PM
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Lé.Skiing
Posts: 10035 - Karma: 8,128
she did say three things... take them into groups of 4, then 2, then one... and the lighter one is fake.... wait something clicked... unless you have luck on your side then you would only need 3... but you would most likely need at most 6 weighs to do it correctly due to varying of where the diamond is.. and plus the way you can tell if its fake is how its cut.. and how te light shines through it... its not the same as a diamond :)
Jun 15 2006 3:38PM
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OpIvy
Posts: 741 - Karma: 9
right, I have found half a dozen ways to do it, all with 4 weighs. I can't figure out how to narrow it down to 3.
Jun 15 2006 3:50PM
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siver-cartel
Posts: 281 - Karma: 104
they might look exactly the same but not weight exactly the same you brain teaser doesn't work
Jun 15 2006 4:10PM
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Badfish2
Posts: 3453 - Karma: 21
I know,
So....
start again.
split the 12 into 3 groups of 4..
label them 1-12

Step 1:
put 1,2,3,4 on the left side and 5,6,7,8 on the right side.

If the left side goes down goto 2a, if the right side goes down, go to 2b.

Step 2a:
put 1,2,5 and 6 on the left and 3,7,9,10 on the right side.

if the left goes down again, go to 3aa, if the right side goes down, go to 3ab.

Step 3aa:
put 1,7 on the left and 9,10 on the right.

if the left goes down - 1 is too heavy and is fake
if the right goes down, 7 is too light,
if it balances, 2 is the fake (too heavy)

Step 3ab:
Put 3, 5 on the left and 9,10 on the right.
-If the left side goes down , then 3 is too heavy.
-If the right side goes down, 5 is too light
-If it balances, then 6 is too light.


Step 2b:
place the same diamonds on the scale 1,2,5,6 on left.. 3,7,9,10 on the right

If the left side goes down, go to 3ba, if the right side goes down goto 3bb.

Step 3ba:
Put 3,5 on the left and 9,10 on the right.
-If the left side goes down then 5 is fake(too heavy).
-If the right side goes down, then #3 is fake (too light)
-If it balances, then 6 is too heavy.

Step 3bb:
Put 1, 7 on the left and 9, 10 on the right.
- If the left side goes down, then 7 is too heavy
- right side goes down, 1 is fake (too light)
- if they balance, #2 is fake (too light)
Jun 15 2006 4:10PM
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futurespin
Posts: 2178 - Karma: 168
heres the answer http://www.golfonline.com/golfonline/features/features/article/0,17742,1140670-2,00.html
Jun 15 2006 4:18PM
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futurespin
Posts: 2178 - Karma: 168
nevermind badfish beat me to it^^
Jun 15 2006 4:19PM
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