RIDDLES! Or, are you smarter than the rest of us?

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silverpig

Lifer
Jul 29, 2001
27,703
12
81
Originally posted by: TuxDave
Originally posted by: silverpig
You have 12 golf balls, 11 of which are the same weight, one of which has a deviant weight, and are allowed to use a balance scale 3 times. BUT, you do not know whether the deviating golf ball is heavier or lighter than the rest. Using the scale 3 times, you have to point out the deviating ball AND tell whether it?s heavier or lighter than the rest.

I hate this riddle cuz the answer is so damn long to explain.

Heh, it is... but it's a good one to think about. Too bad that most people just google the answer. I actually worked through it and got the answer.
 

Descartes

Lifer
Oct 10, 1999
13,968
2
0
Originally posted by: silverpig
Originally posted by: TuxDave
Originally posted by: silverpig
You have 12 golf balls, 11 of which are the same weight, one of which has a deviant weight, and are allowed to use a balance scale 3 times. BUT, you do not know whether the deviating golf ball is heavier or lighter than the rest. Using the scale 3 times, you have to point out the deviating ball AND tell whether it?s heavier or lighter than the rest.

I hate this riddle cuz the answer is so damn long to explain.

Heh, it is... but it's a good one to think about. Too bad that most people just google the answer. I actually worked through it and got the answer.

I thought through a similar problem when I first heard it, and I got the right answer. The variation I heard specified heavier/lighter though.
 

silverpig

Lifer
Jul 29, 2001
27,703
12
81
Originally posted by: Descartes
Originally posted by: silverpig
Originally posted by: TuxDave
Originally posted by: silverpig
You have 12 golf balls, 11 of which are the same weight, one of which has a deviant weight, and are allowed to use a balance scale 3 times. BUT, you do not know whether the deviating golf ball is heavier or lighter than the rest. Using the scale 3 times, you have to point out the deviating ball AND tell whether it?s heavier or lighter than the rest.

I hate this riddle cuz the answer is so damn long to explain.

Heh, it is... but it's a good one to think about. Too bad that most people just google the answer. I actually worked through it and got the answer.

I thought through a similar problem when I first heard it, and I got the right answer. The variation I heard specified heavier/lighter though.

Pfft, that's the easy version. :p
 

LordSnailz

Diamond Member
Nov 2, 1999
4,821
0
0
Originally posted by: silverpig
Originally posted by: Descartes
Originally posted by: silverpig
Originally posted by: TuxDave
Originally posted by: silverpig
You have 12 golf balls, 11 of which are the same weight, one of which has a deviant weight, and are allowed to use a balance scale 3 times. BUT, you do not know whether the deviating golf ball is heavier or lighter than the rest. Using the scale 3 times, you have to point out the deviating ball AND tell whether it?s heavier or lighter than the rest.

I hate this riddle cuz the answer is so damn long to explain.

Heh, it is... but it's a good one to think about. Too bad that most people just google the answer. I actually worked through it and got the answer.

I thought through a similar problem when I first heard it, and I got the right answer. The variation I heard specified heavier/lighter though.

Pfft, that's the easy version. :p

yeah, I can easily tell you the answer if I knew if the deviant ball was heavier or lighter ... argh this pisses me off I can't get it ...
 

silverpig

Lifer
Jul 29, 2001
27,703
12
81
Originally posted by: LordSnailz
Originally posted by: silverpig
Originally posted by: Descartes
Originally posted by: silverpig
Originally posted by: TuxDave
Originally posted by: silverpig
You have 12 golf balls, 11 of which are the same weight, one of which has a deviant weight, and are allowed to use a balance scale 3 times. BUT, you do not know whether the deviating golf ball is heavier or lighter than the rest. Using the scale 3 times, you have to point out the deviating ball AND tell whether it?s heavier or lighter than the rest.

I hate this riddle cuz the answer is so damn long to explain.

Heh, it is... but it's a good one to think about. Too bad that most people just google the answer. I actually worked through it and got the answer.

I thought through a similar problem when I first heard it, and I got the right answer. The variation I heard specified heavier/lighter though.

Pfft, that's the easy version. :p

yeah, I can easily tell you the answer if I knew if the deviant ball was heavier or lighter ... argh this pisses me off I can't get it ...

It's quite complicated actually.
 

Flyermax2k3

Diamond Member
Mar 1, 2003
3,204
0
0
weigh them all to get the overall weight, come up with average
weigh half of them and divide the total by 6, come up wtih average
weigh the other half and divide the total by 6, come up with average
by dividing in half you can isolate the deviant ball from the whole and by weighing two different sets you can see if it's lighter or heavier than the rest
:)
 

XZeroII

Lifer
Jun 30, 2001
12,572
0
0

Put 6 of them in one side, and 6 on the other side. Whichever side is heavier contains the heavier ball. Take those 6 and put 3 on one side and 3 on the other. The heavier side will contain the heavier ball. Take one ball and put it on one side, and put the other on the other side. If one side is heavier, then you have found your heavier ball. If they are the same, then it's the ball you didn't weigh.

Simple
 

Flyermax2k3

Diamond Member
Mar 1, 2003
3,204
0
0
Get this back on the front page!
Here's a new one:
What has 4 legs in the beginning,
2 legs in the middle,
and 3 legs at the end?
 

Descartes

Lifer
Oct 10, 1999
13,968
2
0
Originally posted by: XZeroII
Originally posted by: Flyermax2k3
weigh them all to get the overall weight, come up with average
weigh half of them and divide the total by 6, come up wtih average
weigh the other half and divide the total by 6, come up with average
by dividing in half you can isolate the deviant ball from the whole and by weighing two different sets you can see if it's lighter or heavier than the rest
:)

Using the scale 3 times

Put 6 of them in one side, and 6 on the other side. Whichever side is heavier contains the heavier ball. Take those 6 and put 3 on one side and 3 on the other. The heavier side will contain the heavier ball. Take one ball and put it on one side, and put the other on the other side. If one side is heavier, then you have found your heavier ball. If they are the same, then it's the ball you didn't weigh.

Simple

Except that we just explained that you have to not only find the deviant ball, but also whether it's heavier/lighter.

Not so simple now :)
 

Descartes

Lifer
Oct 10, 1999
13,968
2
0
Originally posted by: Flyermax2k3
Get this back on the front page!
Here's a new one:
What has 4 legs in the beginning,
2 legs in the middle,
and 3 legs at the end?

A male baby?

4 legs == the copulating parents
2 legs == the baby sans developed genitalia
3 legs == well, you get the idea.
 

Flyermax2k3

Diamond Member
Mar 1, 2003
3,204
0
0
Originally posted by: Descartes


Except that we just explained that you have to not only find the deviant ball, but also whether it's heavier/lighter.

Not so simple now :)

My method would determine whether it's heavier or lighter though.... (I dunno if you were addressing me or not, you did quote me...)
 

Flyermax2k3

Diamond Member
Mar 1, 2003
3,204
0
0
Originally posted by: Descartes
Originally posted by: Flyermax2k3
Get this back on the front page!
Here's a new one:
What has 4 legs in the beginning,
2 legs in the middle,
and 3 legs at the end?

A male baby?

4 legs == the copulating parents
2 legs == the baby sans developed genitalia
3 legs == well, you get the idea.

close enough for credit I guess
It's just a person (the "beginning, middle, end" are the points in his/her life)
4 legs when you're a baby and crawl on all fours
2 legs when you're an adult and walk on 2 legs
and 3 legs when you're an old man/woman and walk with a cane
 

silverpig

Lifer
Jul 29, 2001
27,703
12
81
Originally posted by: Flyermax2k3
weigh them all to get the overall weight, come up with average
weigh half of them and divide the total by 6, come up wtih average
weigh the other half and divide the total by 6, come up with average
by dividing in half you can isolate the deviant ball from the whole and by weighing two different sets you can see if it's lighter or heavier than the rest
:)

You only get 3 weighs.

edit: and it's a balance scale. You can't find out how much each ball (or all of them for that matter) weighs, only their relative weights.
 

sillymofo

Banned
Aug 11, 2003
5,817
2
0
Originally posted by: Flyermax2k3
Originally posted by: Descartes
Originally posted by: Flyermax2k3 Get this back on the front page! Here's a new one: What has 4 legs in the beginning, 2 legs in the middle, and 3 legs at the end?
A male baby? 4 legs == the copulating parents 2 legs == the baby sans developed genitalia 3 legs == well, you get the idea.
close enough for credit I guess It's just a person (the "beginning, middle, end" are the points in his/her life) 4 legs when you're a baby and crawl on all fours 2 legs when you're an adult and walk on 2 legs and 3 legs when you're an old man/woman and walk with a cane
Wow... I can't believe people are still getting this riddle wrong. If you haven't lived in a caved and have heard of Greek Mythology, you'd have had the answer for this one since you were 5.
 

silverpig

Lifer
Jul 29, 2001
27,703
12
81
Originally posted by: XZeroII
Put 6 of them in one side, and 6 on the other side. Whichever side is heavier contains the heavier ball. Take those 6 and put 3 on one side and 3 on the other. The heavier side will contain the heavier ball. Take one ball and put it on one side, and put the other on the other side. If one side is heavier, then you have found your heavier ball. If they are the same, then it's the ball you didn't weigh.

Simple

Wrong. It's not given that the deviant ball is heavier. It might be lighter than the rest.
 

Descartes

Lifer
Oct 10, 1999
13,968
2
0
Originally posted by: cr4zymofo
Originally posted by: Flyermax2k3
Originally posted by: Descartes
Originally posted by: Flyermax2k3 Get this back on the front page! Here's a new one: What has 4 legs in the beginning, 2 legs in the middle, and 3 legs at the end?
A male baby? 4 legs == the copulating parents 2 legs == the baby sans developed genitalia 3 legs == well, you get the idea.
close enough for credit I guess It's just a person (the "beginning, middle, end" are the points in his/her life) 4 legs when you're a baby and crawl on all fours 2 legs when you're an adult and walk on 2 legs and 3 legs when you're an old man/woman and walk with a cane
Wow... I can't believe people are still getting this riddle wrong. If you haven't lived in a caved and have heard of Greek Mythology, you'd have had the answer for this one since you were 5.

I lived in a cave in Greece. Does that make a difference?
 

Flyermax2k3

Diamond Member
Mar 1, 2003
3,204
0
0
Originally posted by: silverpig
Originally posted by: Flyermax2k3
weigh them all to get the overall weight, come up with average
weigh half of them and divide the total by 6, come up wtih average
weigh the other half and divide the total by 6, come up with average
by dividing in half you can isolate the deviant ball from the whole and by weighing two different sets you can see if it's lighter or heavier than the rest
:)

You only get 3 weighs.

edit: and it's a balance scale. You can't find out how much each ball (or all of them for that matter) weighs, only their relative weights.

That was 3 times (try counting again) ;) You never stated it was a balance scale either so I should get some kind of credit ;)
 

silverpig

Lifer
Jul 29, 2001
27,703
12
81
Originally posted by: Flyermax2k3
Originally posted by: silverpig
Originally posted by: Flyermax2k3
weigh them all to get the overall weight, come up with average
weigh half of them and divide the total by 6, come up wtih average
weigh the other half and divide the total by 6, come up with average
by dividing in half you can isolate the deviant ball from the whole and by weighing two different sets you can see if it's lighter or heavier than the rest
:)

You only get 3 weighs.

edit: and it's a balance scale. You can't find out how much each ball (or all of them for that matter) weighs, only their relative weights.

That was 3 times (try counting again) ;) You never stated it was a balance scale either so I should get some kind of credit ;)

That method will only tell you which half of the balls has the heavier ball. You basically got nowhere. And:

and are allowed to use a balance scale 3 times

taken from my original post of the question :p
 

XZeroII

Lifer
Jun 30, 2001
12,572
0
0
Originally posted by: Descartes
Originally posted by: XZeroII
Originally posted by: Flyermax2k3
weigh them all to get the overall weight, come up with average
weigh half of them and divide the total by 6, come up wtih average
weigh the other half and divide the total by 6, come up with average
by dividing in half you can isolate the deviant ball from the whole and by weighing two different sets you can see if it's lighter or heavier than the rest
:)

Using the scale 3 times

Put 6 of them in one side, and 6 on the other side. Whichever side is heavier contains the heavier ball. Take those 6 and put 3 on one side and 3 on the other. The heavier side will contain the heavier ball. Take one ball and put it on one side, and put the other on the other side. If one side is heavier, then you have found your heavier ball. If they are the same, then it's the ball you didn't weigh.

Simple

Except that we just explained that you have to not only find the deviant ball, but also whether it's heavier/lighter.

Not so simple now :)

Divide the 12 balls into 3 groups of 4. Weigh 2 of the groups. If they are the same weight, then the devient ball is in the third group. If one is heavier, weigh that against the 3rd group. If it's heavier than the 3rd group, then that one contains the devient ball and it's heavier. If they are the same weight, then the devient ball was in the lighter group and the devient ball is lighter. You then put one ball on one side and the other on the other. If they are the same, then the devient is the third ball. If not, you have your ball.

Oh yea! no google or help of any kind :D
 

Flyermax2k3

Diamond Member
Mar 1, 2003
3,204
0
0
Originally posted by: silverpig
Originally posted by: Flyermax2k3
Originally posted by: silverpig
Originally posted by: Flyermax2k3
weigh them all to get the overall weight, come up with average
weigh half of them and divide the total by 6, come up wtih average
weigh the other half and divide the total by 6, come up with average
by dividing in half you can isolate the deviant ball from the whole and by weighing two different sets you can see if it's lighter or heavier than the rest
:)

You only get 3 weighs.

edit: and it's a balance scale. You can't find out how much each ball (or all of them for that matter) weighs, only their relative weights.

That was 3 times (try counting again) ;) You never stated it was a balance scale either so I should get some kind of credit ;)

That method will only tell you which half of the balls has the heavier ball. You basically got nowhere. And:

and are allowed to use a balance scale 3 times

taken from my original post of the question :p

eh, my method *does* determine if the ball is heavier or lighter. Read my post again. If I have to go get some golf balls and use my method to determine if the deviant ball is heavier or lighter then I won't, but it would be great if I did ;)
I did miss the balance scale thing though ;)
 

RaynorWolfcastle

Diamond Member
Feb 8, 2001
8,968
16
81
Originally posted by: silverpig
Originally posted by: XZeroII
Put 6 of them in one side, and 6 on the other side. Whichever side is heavier contains the heavier ball. Take those 6 and put 3 on one side and 3 on the other. The heavier side will contain the heavier ball. Take one ball and put it on one side, and put the other on the other side. If one side is heavier, then you have found your heavier ball. If they are the same, then it's the ball you didn't weigh.

Simple

Wrong. It's not given that the deviant ball is heavier. It might be lighter than the rest.
I'd explain it but it's friggin long to explain why you do everything the way you do it. It has to do with permutations, I forget the exact procedure to go through but I'm sure I could remember it in a few minutes if I thought about it. IIRC the trick was to use permutations so that you need all 3 weighings regardless of how the first and second weighings turn out.
 

silverpig

Lifer
Jul 29, 2001
27,703
12
81
Originally posted by: XZeroII
Originally posted by: Descartes
Originally posted by: XZeroII
Originally posted by: Flyermax2k3
weigh them all to get the overall weight, come up with average
weigh half of them and divide the total by 6, come up wtih average
weigh the other half and divide the total by 6, come up with average
by dividing in half you can isolate the deviant ball from the whole and by weighing two different sets you can see if it's lighter or heavier than the rest
:)

Using the scale 3 times

Put 6 of them in one side, and 6 on the other side. Whichever side is heavier contains the heavier ball. Take those 6 and put 3 on one side and 3 on the other. The heavier side will contain the heavier ball. Take one ball and put it on one side, and put the other on the other side. If one side is heavier, then you have found your heavier ball. If they are the same, then it's the ball you didn't weigh.

Simple

Except that we just explained that you have to not only find the deviant ball, but also whether it's heavier/lighter.

Not so simple now :)

Divide the 12 balls into 3 groups of 4. Weigh 2 of the groups. If they are the same weight, then the devient ball is in the third group. If one is heavier, weigh that against the 3rd group. If it's heavier than the 3rd group, then that one contains the devient ball and it's heavier. If they are the same weight, then the devient ball was in the lighter group and the devient ball is lighter. You then put one ball on one side and the other on the other. If they are the same, then the devient is the third ball. If not, you have your ball.

Oh yea! no google or help of any kind :D

WRONG. You have 3 groups of 4. You can only do your last step if you have 3 groups of 2. "One ball on one side and the other on the other"... what about the other two balls in the group?
 

bootymac

Diamond Member
Aug 20, 2001
9,597
0
76
Originally posted by: Descartes
Try this one:

There are three switches in a hallway. One switch controls a light fixture in a room at the far end of the hall. The door to the room is closed, and you can't see whether the light is on or off. You need to find out which of the three switches controls the light. How can you be certain of finding that out, making just one trip to the room?

[edit]I'll tell everyone what answer I gave if no one gets it.[/edit]

Why don't I just turn on all 3 switches and go to the room?
 

silverpig

Lifer
Jul 29, 2001
27,703
12
81
Originally posted by: Flyermax2k3
Originally posted by: silverpig
Originally posted by: Flyermax2k3
Originally posted by: silverpig
Originally posted by: Flyermax2k3
weigh them all to get the overall weight, come up with average
weigh half of them and divide the total by 6, come up wtih average
weigh the other half and divide the total by 6, come up with average
by dividing in half you can isolate the deviant ball from the whole and by weighing two different sets you can see if it's lighter or heavier than the rest
:)

You only get 3 weighs.

edit: and it's a balance scale. You can't find out how much each ball (or all of them for that matter) weighs, only their relative weights.

That was 3 times (try counting again) ;) You never stated it was a balance scale either so I should get some kind of credit ;)

That method will only tell you which half of the balls has the heavier ball. You basically got nowhere. And:

and are allowed to use a balance scale 3 times

taken from my original post of the question :p

eh, my method *does* determine if the ball is heavier or lighter. Read my post again. If I have to go get some golf balls and use my method to determine if the deviant ball is heavier or lighter then I won't, but it would be great if I did ;)
I did miss the balance scale thing though ;)

It will eventually, but it'll take something like 6 weighs.

Weigh 1: get total weight
Weigh 2: get weight of one half
Weigh 3: get weight of other half

There's no way you can isolate a single ball with these three weighs.
 

silverpig

Lifer
Jul 29, 2001
27,703
12
81
Originally posted by: bootymac
Originally posted by: Descartes
Try this one:

There are three switches in a hallway. One switch controls a light fixture in a room at the far end of the hall. The door to the room is closed, and you can't see whether the light is on or off. You need to find out which of the three switches controls the light. How can you be certain of finding that out, making just one trip to the room?

[edit]I'll tell everyone what answer I gave if no one gets it.[/edit]

Why don't I just turn on all 3 switches and go to the room?

Because then the light will definitely be on for sure. Which switch really turned the bulb on?