This could as well go to the Forum Games section, but I decided it would work here better.

I'll post a puzzle. (math, logic, optic, etc.) The next person should post the answer, possibly the way they solved it, and post a second puzzle. The third person solves the second, and so on.

Two friends imported a 16-gallon barrel of wine. One friend was to keep the barrel and half the wine, while the other was to keep the other half in his own, 11 gallon bottle. He also had a 6 gallon bottle, which can be used, with the other two, by pouring the wine from one to another, to divide the 16 gallons of wine into two equal portions.

Write down how they should do this, in the following format:
(if there would have been an 8-gallon barrel, and 5- and 3-gallon bottles)
8-0-0
3-5-0
3-2-3
6-2-0
6-0-2
1-5-2
1-4-3
4-4-0

numbers correspond to the barrel, 11 gallon container, and 6 gallon container respectively.

16-0-0
10-0-6
0-10-6
6-10-0
6-4-6
12-4-0
12-0-4
1-11-4
1-9-6
7-9-0
7-3-6
13-3-0
13-0-3
2-11-3
2-8-6
8-8-0

There was probably a faster way to do that.

Which number does not belong:
145
325
550
100
505
640

(from my puzzle calendar)

I tend to dislike these, because no matter what it always seems like their arbitrary pattern/grouping is no less arbitrary than any guess that you can come up with.

The only arbitrary thing that I can come up with that seems at all decent is that 505 has the largest (and only 3 digit) prime factor of 101. (If somehow I am right I will post a riddle upon confirmation that I am correct. Which I shouldn't be.)

Want a hint?

(I will admit that the page-a-day calendar I got this from is the worst puzzle calendar I have ever owned)

I concur with Deckmaster: these puzzles assume you think like their author. Guy's Strong Law of Small Numbers suggests that there are too many potential patterns here to determine, without a cheat-sheet, which one(s) the author had in mind.

That said, I posit 550, on the completely spurious grounds that it is the only number on that list without an entry in Prime Curios.

next puzzle anyone?

The digits all add to 10. Except for 100.

Bah, too trivial.

I noted that in passing, but instead concluded "they're all one more than a multiple of 9", which was unhelpful.

if not,
here:

disprove the following:
Imagine a triangle with corners A,B, and C
points D, E, and F are the centers of each if its sides.
now, draw line segments DF and EF (in your mind, or on your recently drawn triangle).

We know that DF=1/2BC=BE

• ---//------ EF=1/2AB=BD

Therefore, the sum of the lengths of line segments AD,DF,FE, and EC=AB+BC
if we repeat the above process in triangles ADF and FCE (here, again, the zig-zagged line is equal AB+BC), then repeat it again in the triangles created (here, again, the zig-zagged line is equal AB+BC), etc., the zig-zag lines will get closer and closer to AC, and finally join it. The length of that final zig-zagged line will be equal to AC, and, to AB+BC. Therefore, in any triangle, every one side (AC)will be equal to the sum of the others.

If you take a A-45, B-45, C-90 triangle for example (C in the lower right) and you take it in once from the top(B), you have two triangles with sides .5AC=.5BC=.5AB/√(2), if you take in the two tops once the ratio is still the same: .25AC=.25BC=.5AB/√(2). no matter how many (n) little triangles you have, the ratio stays (1/n)AC=(1/n)BC=(1/n)AB/√(2). when you add up all the little edges of the triangles you get the original perimeter.
(that was a lousy explanation, I need a white board)

A man was driving his car with the radio on. Suddenly, it stopped working. He then drove off a cliff and died. Why did he do so?
(You may ask questions with a yes/no answer. Do not answer if you have heard the question before.)

I know this one. should I give the answer?

I'm just going to take a guess, and assume that the word "it" in the second sentence referred to the car, not the radio as we are expected to assume. Specifically, the brakes stopped working. This feels like a dumb answer, but completely plausible. Actually, let me just reword that into a question. Does the "it" in the second sentence refer to the radio?

yes.

The city off in the distance was hit by a nuclear bomb (where the radio station was and which is why the radio stopped). The flash of the blast blinded him causing him to drive off the cliff?

No.

Honestly, I think Blake should win just for having such an awesome answer.

But it lacks the acute investigative instinct of Hercule Poirot.

Question: Was the man motivated to drive of the cliff?

did Person ever say if Ph1n's assumption was correct?

Yes

It was not.

was the radio telling him to do something which had previously prevented him from going off the cliff?

No.

Was the man related to the radio station in any way?

Was the radio a typical car radio (plays audio, AM/FM tuner)?