Poisoned bottle riddle:

You have a wine cellar that contains 1000 bottles of wine.  Unfortunately, your evil rival sneaked in and poisoned some of the bottles (stuck a needle in the cork with poison, let's say).  You have no idea which ones or even how many were poisoned.  But you LOVE your wine, and can't spare to throw all 1000 bottles out.  You just happen to be a researcher and have at your disposal 10 lab rats and you plan to feed them each some wine, in some way, to discover which bottles are poisoned bottles (you feel bad about killing the rats, but DAMN you love your wine).

What do you do to determine ALL of the poisoned bottles?

Timing fuses riddle:

You have a long firecracker fuse (just the fuse, no firecracker).  It burns at an unknown and variable rate.  Meaning some sections of the fuse can burn very quickly, others area may burn very slowly.  You have no idea what parts of the fuse may burn fast or slow, but you know that if you lit the fuse and let it burn all the way down, EXACTLY 60 min will pass.

You have a 2nd fuse that is similar to the 1st fuse in that it burns at a variable rate, you have no idea where it will burn fast/slow, and if you lit it, it will burn all the way down in exactly 60 min.  However, it is not identical to the first fuse in that the two fuses will have different areas that will burn fast/slow.

Now, all you have are the two fuses and a lighter.  Measure out exactly 45min of time.

Note: My last three riddles were asked to me on various job interviews over the years, to test my spacial/logical reasoning skills. (and yes, I solved them - I wouldn't ask a riddle to someone else that I wasn't able to solve myself).

I have some other good ones that I'll try to remember correctly when I have time.

This is fun!

Slander wrote:

Find the defective bottle riddle:

You have 5 bottles, each filled with pills.  4 of the bottles contain all normal pills, where each pill weighs 10 grams each.  The other bottle contains all defective pills, which weigh only 9 grams each (yes - these are monster pills!).  You have no idea which bottle contains the defective pills, you can't tell by looking at them, and you have a normal digital scale to tell you the weight, in grams, of the pills you place on it.  You can place as many pills on the scale, from any of the bottles, but you can make only a SINGLE weighing.

Locate the defective bottle of pills.  And do it by weighing the fewest number of pills possible (and how many is that?)

I would weight 10 pills : 1 from bottle 1, 2 from bottle 2, 3 from bottle 3 and 4 from bottle 4 (none from bottle 5).

If I get a total weight of 100 grams, then the defective pills are in bottle 5.

If I get a total weight of 99 grams, then the defective pills are in bottle 1.

If I get a total weight of 98 grams, then the defective pills are in bottle 2.

If I get a total weight of 97 grams, then the defective pills are in bottle 3.

If I get a total weight of 96 grams, then the defective pills are in bottle 4.

Can't do better.

Slander wrote:

Timing fuses riddle:

Light both ends of fuse 1. When it stop burning, fold fuse 2 in half twice and light both ends (including the folds) when it stops burning 45 minutes have gone by.

Slander wrote:

So the best I can do is 14 drops using the above methodology.

Bravo - This is the answer I came up with too, and is the best I've heard.  If anyone else can get one smaller, feel free to show it.

Slander wrote:

BorisTheFrugal wrote:

6oz of Water:

So, 8 steps??  It seems I should be able to do better, but it's late and my head hurts after doing the ball drop one

Bravo again.  It's the concept of moving the 1 oz from one glass to the second, and then using the remaining space in it to decrease a different glass that most people can't get.

Slander wrote:

Poisoned bottle riddle:

You have a wine cellar that contains 1000 bottles of wine.  Unfortunately, your evil rival sneaked in and poisoned some of the bottles (stuck a needle in the cork with poison, let's say).  You have no idea which ones or even how many were poisoned.  But you LOVE your wine, and can't spare to throw all 1000 bottles out.  You just happen to be a researcher and have at your disposal 10 lab rats and you plan to feed them each some wine, in some way, to discover which bottles are poisoned bottles (you feel bad about killing the rats, but DAMN you love your wine).

What do you do to determine ALL of the poisoned bottles?

3 Question:

1) I'm assuming that I can feed a rat as much wine as I want, and they won't die from it?
2) Can I reuse live rats? (if I feed them something as a test and they don't die from poisoning, can I feed them more)
3) Is the poisoning immediate?

Slander wrote:

Poisoned bottle riddle:

You have a wine cellar that contains 1000 bottles of wine.  Unfortunately, your evil rival sneaked in and poisoned some of the bottles (stuck a needle in the cork with poison, let's say).  You have no idea which ones or even how many were poisoned.  But you LOVE your wine, and can't spare to throw all 1000 bottles out.  You just happen to be a researcher and have at your disposal 10 lab rats and you plan to feed them each some wine, in some way, to discover which bottles are poisoned bottles (you feel bad about killing the rats, but DAMN you love your wine).

What do you do to determine ALL of the poisoned bottles?

let them breed. and pace yourself on the drinking.

ratsy wrote:

Slander wrote:

Timing fuses riddle:

 

Light both ends of fuse 1. When it stop burning, fold fuse 2 in half twice and light both ends (including the folds) when it stops burning 45 minutes have gone by.

Step 1 gives you 30 minutes, check.  But step 2 doesn't give you 15 minutes, surely?  It's equivalent to cutting the fuse into four equal length segments and burning all of them from both ends simultaneously.  If the fuse was uniform-burning, they'd all burn out in 7 1/2 minutes.

I think you're on the right track, but in step one I'd light both ends of fuse 1 and one end of fuse 2.  When fuse 1 burns out light the other end of fuse 2.

weathertop wrote:

let them breed. and pace yourself on the drinking.

Bravo WT....now THAT is some ingenuity.

Defective bottle solution?

On the scale, place

4 from A
3 from B
2 from C
1 from D
0 from E 

90 = E, 89 = D, 88 = C, etc..

M57 wrote:

Defective bottle solution?

On the scale, place

4 from A
3 from B
2 from C
1 from D
0 from E 

90 = E, 89 = D, 88 = C, etc..

 Just what I said on post #84 but without a calculation mistake ;)

I would weight 10 pills : 1 from bottle 1, 2 from bottle 2, 3 from bottle 3 and 4 from bottle 4 (none from bottle 5).

If I get a total weight of 100 grams, then the defective pills are in bottle 5.

If I get a total weight of 99 grams, then the defective pills are in bottle 1.

If I get a total weight of 98 grams, then the defective pills are in bottle 2.

If I get a total weight of 97 grams, then the defective pills are in bottle 3.

If I get a total weight of 96 grams, then the defective pills are in bottle 4.

NewlyIdle wrote:

ratsy wrote:

Slander wrote:

Timing fuses riddle:

 

Light both ends of fuse 1. When it stop burning, fold fuse 2 in half twice and light both ends (including the folds) when it stops burning 45 minutes have gone by.

Step 1 gives you 30 minutes, check.  But step 2 doesn't give you 15 minutes, surely?  It's equivalent to cutting the fuse into four equal length segments and burning all of them from both ends simultaneously.  If the fuse was uniform-burning, they'd all burn out in 7 1/2 minutes.

I think you're on the right track, but in step one I'd light both ends of fuse 1 and one end of fuse 2.  When fuse 1 burns out light the other end of fuse 2.

Very clever. Did not find it.

Toto wrote:

M57 wrote:

Defective bottle solution?

On the scale, place

4 from A
3 from B
2 from C
1 from D
0 from E 

90 = E, 89 = D, 88 = C, etc..

 Just what I said on post #84 but without a calculation mistake ;)

I would weight 10 pills : 1 from bottle 1, 2 from bottle 2, 3 from bottle 3 and 4 from bottle 4 (none from bottle 5).

If I get a total weight of 100 grams, then the defective pills are in bottle 5.

If I get a total weight of 99 grams, then the defective pills are in bottle 1.

If I get a total weight of 98 grams, then the defective pills are in bottle 2.

If I get a total weight of 97 grams, then the defective pills are in bottle 3.

If I get a total weight of 96 grams, then the defective pills are in bottle 4.

 

Correct.

NewlyIdle wrote:

ratsy wrote:

Slander wrote:

Timing fuses riddle:

 

Light both ends of fuse 1. When it stop burning, fold fuse 2 in half twice and light both ends (including the folds) when it stops burning 45 minutes have gone by.

Step 1 gives you 30 minutes, check.  But step 2 doesn't give you 15 minutes, surely?  It's equivalent to cutting the fuse into four equal length segments and burning all of them from both ends simultaneously.  If the fuse was uniform-burning, they'd all burn out in 7 1/2 minutes.

I think you're on the right track, but in step one I'd light both ends of fuse 1 and one end of fuse 2.  When fuse 1 burns out light the other end of fuse 2.

NewlyIdle's solution is correct, of course.

If you cut a fuse (which is what ratsy was effectively doing), you throw away information.

BorisTheFrugal wrote:

Slander wrote:

Poisoned bottle riddle:

3 Question:

1) I'm assuming that I can feed a rat as much wine as I want, and they won't die from it?
2) Can I reuse live rats? (if I feed them something as a test and they don't die from poisoning, can I feed them more)
3) Is the poisoning immediate?

 

1) Correct

2) Yes.  You can feed wine to a rat until it either dies of poison, or it will live.  A rat won't die from wine alone.  You're a researcher and you love wine, so you've made super rats that can drink a STAGGERING amount of wine :)  But it's a deadly poison, so only a few drops of wine would kill you.

3) No - it takes about 1-2 hours to kick in and kill you.  So in theory, you'd have enough time to feed a little wine from each bottle to a single rat before he died from the poison - even if the first bottle he drank from was poisoned.

weathertop wrote:

let them breed. and pace yourself on the drinking.

ahahahah.  The original version of this riddle (or at least the one I heard) was that you had 10 servants working for you because you were rich enough to have 1000 bottles of wine that you cared that much about.  And you'd poison your servants to figure it out.  So at least I toned it down a little by going to rats

1 pill from the first bottle, 2 from 2nd, etc. None from fifth bottle.

So 1+2+3+4=10 pills.

If weight ends in 9 - 1st bottle is defective

8 - 2nd bottle is defective

7 - 3rd bottle

6 - 4th bottle

0 - 5th bottle.

Is there a better solution?

Ozyman wrote:

1 pill from the first bottle, 2 from 2nd, etc. None from fifth bottle.

So 1+2+3+4=10 pills.

If weight ends in 9 - 1st bottle is defective

8 - 2nd bottle is defective

7 - 3rd bottle

6 - 4th bottle

0 - 5th bottle.

Is there a better solution?

Not that I know of - that's it.  Same as was found above by Toto and M57.