The Hardest Riddle I Know

[Colleen Thomas]

Brilliant Colly !

PITA. I hate it when I am forced to get out the paper & pencil to solve one of these buggers

-Colly

 

[neonlyte]

My excuse is trying to watch the football at the same time

I tried the 4, 4, 4 route but failed to spot swapping one in from the unweighed group was the solution.

 

[Nemasis Enforcer]

PITA. I hate it when I am forced to get out the paper & pencil to solve one of these buggers

-Colly

Colly this is the best way I can put it...

http://www.planetsmilies.com/smilies/love/love30.gif

Brillient!!

 

[mcfbridge]

All right. The hard way then.

1.) Break em up into sets of four (A, B, C) then measure A vs B.

If they balance your odball is in set C. (case A)
If not then it is in A or B (Case B)

2-a).If your oddball is in C, then measure 3 C's vs. 3 As. Should they balance your 4th C was the odd. Should they not and the C side falls then one c is heavy, if they rise then 1 C is light.

3-a) You then weight c vs c. If they balance, you have your oddball in hand, if not, since you now know your C is heavy or light, you have your answer by which dise is heavy or light.

On the other hand if A or B is not in balance then you know C is all regular. this leades to case B.

Gets ugly if A & B don't balance. But you know by the scale you either have a heavy A or a light B if the A side falls or a heavy B or light a if the B side falls.

Reset your groups. (A1,A2,A3, C1) (B1,B2,B3,A4) (C2,C3,C4,B4)

2-B) Measure (B1,B2,B3,A4) vs (C2,C3,C4,B4)

If they Balance your oddball is in (A1,A2,A3, C1) (Case B1)
3-B1) then Measure A1 vs A2, if they balance A3 is odd, if they don' you will by the above you know your A was heavy or light, so if it's light the one that rises is your odd ball, if they are heavy the one that falls is your oddball.

If they don't balance (Case B2)

3-B2)You measure A4 vs. any C. If they balance you know you have a light B, if they don't then you are holding the Heavy A.

3-b3) If it's a light B, weight B1 Vs B2. If they balance B3 is your odd ball, if they don't, the one theat rises is your light B.

The hard way.


-Colly

Very good, but I think you using it 4 times.

You measure 4x4

then you do (B1,B2,B3,A4) vs (C2,C3,C4,B4)

If they don't balance you do A4 vs any C

If that doesn't balance, you still have the b1, b2, and b3 left and you are no out of chance.

If I am not seeing your answer correctly, please let me know.

 

[Colleen Thomas]

My excuse is trying to watch the football at the same time

I tried the 4, 4, 4 route but failed to spot swapping one in from the unweighed group was the solution.

It's all about gaining a control set in the first weighing. Until you have controls you are working a problem with no known quantity. 4V4 is the only way I could see to get a control set in the first weighing that covered all the balls.

-Colly

 

[smutpen]

Very good, but I think you using it 4 times.

You measure 4x4

then you do (B1,B2,B3,A4) vs (C2,C3,C4,B4)

If they don't balance you do A4 vs any C

If that doesn't balance, you still have the b1, b2, and b3 left and you are no out of chance.

If I am not seeing your answer correctly, please let me know.

I think you fell into the same trap as the rest of us, Colleen.
Your step 3-b3 looks like a fourth measurement.

Grrrrr....

 

[Colleen Thomas]

Ok, here is the long break down:



Divide the balls into three groups of four A, B and C.
Weigh A vs. B. If they balance your oddball is in C.

So wiegh 3 of the C set vs. 3 of the A set. If they balance the oddball is in your hand, if they rise the odd C is light, if they fall the odd C is Heavy. Weigh a C vs. C, if they balance the oddball is in your hand, otherwise the one that rises of falls is the oddball, depending upon whether you determined the odd C is heavy or light in step 2.

If the A side falls it mean you have a heavy A or light B. So rearange your sets to (A1,A2,A3,C1) (B1,B2,B3,A4) and (C2,C3,C4,B4)

Now weight (B1,B2,B3,A4) vs (C2,C3,C4,B4)

If they balance your oddball is in (A1,A2,A3,C1) Since we know the B's are all even now, we know we a re looking for a heavy A. So weigh A vs. A. If they balance you are holding the oddball, if they don't the side that falls is your odd one cause we know we are looking for a heavy A.

If (B1,B2,B3,A4) falls it means the A in (B1,B2,B3,A4) is heavy or the B in (C2,C3,C4,B4) is light. So weigh your A vs any C. If the A falls, it's heavy, if they balance the B in (c2,C3,C4,B4) is light.

or

If (C2,C3,C4,B4) falls you have a light B. Weigh B vs. B from (b!,B2,B4, A4) if they balance you are holding the light B, other wise the one that rises is the light B.


If B falls you have either a heavy B or a light A. So rearrange the balls to (A1,A2,A3,B4) (B1,B2,B3,C4) (C1,C2,C3,A4).
Wight (A1,A2,A3,B4) vs (C1,C2,C3,A4). If they balance, your oddball is in the other group. that makes it a heavy B so weigth b vs B. If they balance the oddball is in hand, if they don't the one that falls is odd.

If (A1,A2,A3,B4) falls then the B in this set is heavy or the A in the other is light. Weigh the B vs. Any c. If they balance your A is the odd ball. If they don't the B that falls is your odd ball.

Or

if the (C1,C2,C3,A4) falls then it means an A in (A1,A2,A3,B4) is light. So you just weigh A vs A. If they balance you are holding the odd ball, if not the one that rises is the light A.

I'm pretty sure I am write, although it's easier to show in diagram than explain in words.

-Colly

 

[mcfbridge]

Ok, here is the long break down:



Divide the balls into three groups of four A, B and C.
Weigh A vs. B. If they balance your oddball is in C.

So wiegh 3 of the C set vs. 3 of the A set. If they balance the oddball is in your hand, if they rise the odd C is light, if they fall the odd C is Heavy. Weigh a C vs. C, if they balance the oddball is in your hand, otherwise the one that rises of falls is the oddball, depending upon whether you determined the odd C is heavy or light in step 2.

If the A side falls it mean you have a heavy A or light B. So rearange your sets to (A1,A2,A3,C1) (B1,B2,B3,A4) and (C2,C3,C4,B4)

Now weight (B1,B2,B3,A4) vs (C2,C3,C4,B4)

If they balance your oddball is in (A1,A2,A3,C1) Since we know the B's are all even now, we know we a re looking for a heavy A. So weigh A vs. A. If they balance you are holding the oddball, if they don't the side that falls is your odd one cause we know we are looking for a heavy A.

If (B1,B2,B3,A4) falls it means the A in (B1,B2,B3,A4) is heavy or the B in (C2,C3,C4,B4) is light. So weigh your A vs any C. If the A falls, it's heavy, if they balance the B in (c2,C3,C4,B4) is light.

or

If (C2,C3,C4,B4) falls you have a light B. Weigh B vs. B from (b!,B2,B4, A4) if they balance you are holding the light B, other wise the one that rises is the light B.


If B falls you have either a heavy B or a light A. So rearrange the balls to (A1,A2,A3,B4) (B1,B2,B3,C4) (C1,C2,C3,A4).
Wight (A1,A2,A3,B4) vs (C1,C2,C3,A4). If they balance, your oddball is in the other group. that makes it a heavy B so weigth b vs B. If they balance the oddball is in hand, if they don't the one that falls is odd.

If (A1,A2,A3,B4) falls then the B in this set is heavy or the A in the other is light. Weigh the B vs. Any c. If they balance your A is the odd ball. If they don't the B that falls is your odd ball.

Or

if the (C1,C2,C3,A4) falls then it means an A in (A1,A2,A3,B4) is light. So you just weigh A vs A. If they balance you are holding the odd ball, if not the one that rises is the light A.

I'm pretty sure I am write, although it's easier to show in diagram than explain in words.

-Colly

I agree, you have found a solution, congratulations, I'm impressed.

 

[mcfbridge]

Since Colleen has found an answer, I'll post the classic solution.


1. Weight 4 balls vs 4 ball.

I won't bother to post what to do if this balances, that's the easy part.


Lets assume they don't balance. Then one side dropped and the other side rose. If the ball is in the 4 that dropped it's heavier. If it's in the one that rose it's lighter. We will call these group H and group L for short.

2. Weight 2 of the H balls and one L ball, against the other two H balls and one L ball.
If it balances it's one of the two remaining Ls and that's easy.

If it doesn't balance, it is either one of the 2Hs in the basket which fell, or the single L in the basket which rose.

3. Weigh the two Hs in the basket that fell against each other.
If they balance, it's the L ball.
If they don't, it's whichever one drops.




Once again, congratulations Colleen.

 

[Guest]

I agree, you have found a solution, congratulations, I'm impressed.

Impressed ain't the word!

Awesome, Colly! Well done!

Lou

P.S. Mike, that was a toughy, I got nowhere near it.

 

[Colleen Thomas]

I agree, you have found a solution, congratulations, I'm impressed.

I'm glad i'm not a technical writer. Laying it out in words was almost as difficult as figuring out how to do it

-Colly

 

[Nemasis Enforcer]

Impressed ain't the word!

Awesome, Colly! Well done!

Lou

P.S. Mike, that was a toughy, I got nowhere near it.

I agree to I wish I was that smart!!!

 

[smutpen]

I'm glad i'm not a technical writer. Laying it out in words was almost as difficult as figuring out how to do it

-Colly

Very nice!

Interesting how yours differs from the textbook answer, though both share the key elements of identifying the groups as light and heavy and then swapping the members of the sets to isolate the info you need.

It's so much easier to identify what the key elements really are, after someone else has been smart enough to solve the puzzle...

 

[Tanuki]

Well done Colleen! I had to give it a break, my head was hurting!

 

[dr_mabeuse]

Are we able to tell one ball bearing from another? Or do we lose track of their identities whenever we put them in the balance? I mean, are they numbered or something?

--Z

 

[Boboosethemoose]

To all who like that riddle, here is another one for you.

"I make blind men see and seeing men blind,
I can also tell time."
What am I?

There is two answers to this riddle, so have fun trying to find the answers.

 

[gauchecritic]

To all who like that riddle, here is another one for you.

"I make blind men see and seeing men blind,
I can also tell time."
What am I?

There is two answers to this riddle, so have fun trying to find the answers.

You're probably a laser and lying about telling the time.

Gauche

Edited to add for anyone that watches Little England: "I am clear yet coloured, solid yet liquid, I am jelly, what am I?"

 

[gothgodess]

I apologise for being slow as well as stupid. I really should learn to read you know.

 

[gothgodess]

is it the sun?

The blind can often see light.
the seeing are blinded by the sun
and its position tells time

 

[CharleyH]

LOL - seems the hardest riddle for Litsters is how to spell your name. Have come across 4 versions so far, and I think it's climbing.

 

[Nemasis Enforcer]

Ok then whats...

Big, Purple and Eats People???

I'll Answer later after a few guesses

 

[SummerMorning]

It's a mutant turnip!

 

[Nemasis Enforcer]

It's a mutant turnip!

Good try but nope lmao

 

[Nemasis Enforcer]

Ok then whats...

Big, Purple and Eats People???

I'll Answer later after a few guesses

Your all gonna kick yourself when I tell you coz its so obvious!!!

 

[Guest]

Your all gonna kick yourself when I tell you coz its so obvious!!!

The one eyed, one horned, flying purple people eater?

Lou (got that damn song in my head now!)