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shihouzhuge
Nov 28, 2009, 08:37 AM
Hi,everyone!

How to get the bad ball between 12 balls in 3 times only?
I mean, there's a balance ,which has no measures.
What's more, we don't know whether the bad ball is too light or not.

The question confused me,if anyone has some ideas, just tell me, and I do hope we could discuss the problem... :)

mathwiz3502
Nov 29, 2009, 06:27 AM
Professor Layton and the Curious Village Walkthough: 131 Heavier or Lighter? (http://professorlaytonwalkthrough.blogspot.com/2008/02/puzzle131.html)

mathwiz3502
Nov 29, 2009, 06:27 AM
This should help

shihouzhuge
Nov 29, 2009, 07:04 AM
Professor Layton and the Curious Village Walkthough: 131 Heavier or Lighter? (http://professorlaytonwalkthrough.blogspot.com/2008/02/puzzle131.html)

Hi,mathwiz3502.
I think there's something wrong with your link or I have no authority to get in.
Thanks!

mathwiz3502
Nov 29, 2009, 07:20 AM
Try again, and if that doesn't work Google Curious Village heavier or lighter, it is the answer to your question

shihouzhuge
Nov 29, 2009, 07:29 AM
Try again, and if that doesn't work google Curious Village heavier or lighter, it is the answer to your question

Would you mind just pating the answer for me, please?:)
It's greatly appreciated that you do it, and I think I would like to dicuss the problem here.

Thanks!

mathwiz3502
Nov 29, 2009, 07:41 AM
Ok, first of all lets think about 1/3 of the problem
Lets say you put 4 on both sides and they are equal
Then you have 4 unknown balls
Now, you weigh two unknown balls with two "100% equal" balls

If it shifts weigh the two unknown balls again 1 on each side and the one that shifts the same way is the one

If it doesn't shift weigh on of the balls you never weighed to any "100% equal ball" and if it shifts it is it if it doesn't the other ball is it
OK

mathwiz3502
Nov 29, 2009, 07:42 AM
On is one, sorry

shihouzhuge
Nov 29, 2009, 07:43 AM
By the way, I have an another question.

Could you tell me what is the difference between "He goes to the grocery for buying some goods" and "He goes to the grocery to buy some goods ", please?

Thanks!

mathwiz3502
Nov 29, 2009, 07:49 AM
I really don't understand how for is used.

shihouzhuge
Nov 29, 2009, 07:50 AM
Ok, first of all lets think about 1/3 of the problem
lets say you put 4 on both sides and they are equal
then you have 4 unknown balls
Now, you weigh two unknown balls with two "100% equal" balls

if it shifts weigh the two unknown balls again 1 on each side and the one that shifts the same way is the one

if it doesnt shift weigh on of the balls you never weighed to any "100% equal ball" and if it shifts it is it if it doesnt the other ball is it
ok

Thanks!

First "if" that you said was correct, but the second one wasn't. I mean, you don't know the ball is heavier or lighter...

mathwiz3502
Nov 29, 2009, 07:52 AM
Sorry, I just read you profile and I don't believe you will hear "he goes to the grocery (store) for buying some goods" from anyone

mathwiz3502
Nov 29, 2009, 07:56 AM
OK, if those two balls balance you know they are equal totaling 10 equal balls that you know.
Then if you weigh one unknown ball with a "100% equal" ball then if it balances you have process of elimination because you know 11 "equal" balls so the one you never weighed
If it shifts that unknown ball has to be it because it is different from an "equal" ball

mathwiz3502
Nov 29, 2009, 07:58 AM
Add to the third line "is the unbalanced one"

shihouzhuge
Nov 29, 2009, 08:01 AM
I really don't understand how for is used.

Thanks! I think for is not correct in that way...

shihouzhuge
Nov 29, 2009, 09:24 PM
I've done it this morning, and I think it's a quiet difficult problem, because it needs patience!
Now I'm going to post it, if one isn't a patient one just take it easy and you never understand what I say...
First, we have to divide the 12 balls into 3 groups, like A,B, and C.
Second, we weighe A and B. There're three possibilities:

1.A equals B, so we know the bad ball is in the group C, and it's a quiet easy question. For example, we mark the 4 balls in the group C as c1,c2,c3,c4. Then, weigh c1 and c2, there're 3 possibilities, if c1 equals c2, we just weigh c3 and another normal ball in group A, and we know which ball is the bad one. And if c1 lighter than c2, we just weigh c1 and another normal ball, then the question is solved.

2.A is lighter than B: now you have to take a paper or pen to draw what I say, or it's hard for you to understand!
We mark the 8 balls as a1,a2,a3,a4 and b1,b2,b3,before.
Take a4 and before off, then switch a1 and b1,I mean, we will weigh (b1,a2,a3) and (a1,b2,c3),there're 3 possibilities:
First, (b1,a2,a3) still is lighter than (a1,b2,c3), we could make sure the bad one is a2 or a3 or b2.
Then we weigh a2 and a3, if a2 is lighter than a3, we could know the bad one is lighter than other balls, and a2 is the bad one!
Because of the first weigh we've already known a2+a3 must be lighter than two normal balls!
Second, (b1,a2,a3) equals (a1,b2,c3), we could make sure the bad one is in (a4,before,b3), then we b3 and before, if b3 equals before we could know the bad one is a4. And if b3 is heavier than before ,we could make sure the bad one is b3or before, then we've known that (b3+b4) must be heavier than two normals balls, so the heavier one is the bad ball!

3.A is heavier than B, the situation is like the second one.
Good luck for reading this thread, and I think it's a challengeing problem.
It helps us to think in a multidimensional way.

mathwiz3502
Nov 30, 2009, 04:10 PM
That's it shihouzhuge! But quiet is a homophone and quite sounds the same way. Quite means what you used multiple times in your response and quiet means soft.
Good job

shihouzhuge
Nov 30, 2009, 09:14 PM
That's it shihouzhuge! But quiet is a homophone and quite sounds the same way. Quite means what you used multiple times in your response and quiet means soft.
Good job

:DThanks,mathwiz3502. But I don't know what you exactly mean in " But quiet is a homophone and quite sounds the same way. Quite means what you used multiple times in your response and quiet means soft. ":confused:

mathwiz3502
Dec 1, 2009, 03:33 PM
You used quiet in your response right, well quiet means soft, the word you are looking for is quite

shihouzhuge
Dec 1, 2009, 09:03 PM
Hi again, mathwiz3502. Now I get it.

It's a wrong word that I used in my thread, but I think it's too late for me to modify it...

You're a quite careful boy, Thanks!

Unknown008
Dec 2, 2009, 08:45 AM
Ok, just saw that post after my internet connection was re-established.

I wasn't understanding what had to be done until shihouzhuge posted the solution.

Also, mathwiz, the member called unknown008sucks is an annoying person who got banned as soon as (s)he posted something. It's sad how people try to copy my username :rolleyes:

EDIT: Oh, that that thread fits better in 'Mathematics' or 'Other Science' boards. Just saying...

shihouzhuge
Dec 2, 2009, 09:31 PM
Ok, just saw that post after my internet connection was re-established.

I wasn't understanding what had to be done until shihouzhuge posted the solution.

Also, mathwiz, the member called unknown008sucks is an annoying person who got banned as soon as (s)he posted something. It's sad how people try to copy my username :rolleyes:

EDIT: Oh, that that thread fits better in 'Mathematics' or 'Other Science' boards. Just saying...

Hi, Unknown008. It's good to see you here.:)
I don't know the reason why the user wasn't agree with you... I think you are a quite interesting person. Just take it easy.:)

I would like to move this thread to 'Mathematics' boards.

Thanks!