# New Riddles/ Brain Teasers Needed! **URL:** \ **Category:** The Game Room\ **Created:** [August 31, 2015, 9:31pm UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546 "2015-08-31T21:31:57Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 5, 2015, 11:36pm UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/61 "2015-09-05T23:36:32Z")
Wow, that was quick, **Dr. Strangelove**. Had you noticed that one before, yourself? ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [September 6, 2015, 12:01am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/62 "2015-09-06T00:01:50Z")
> [@Chronos](#): > > Wow, that was quick, **Dr. Strangelove**. Had you noticed that one before, yourself? I hadn’t. But I might have perused a list of common verbs :). Actually, I’d hoped you’d have a different one! Good puzzle, though. I was amused at certain near-misses. Like, “to flower” is a verb, but it’s not the verb form of “a flow”. Or “to flicker” is not the verb of “a flick” (though a [movie] flick might indeed flicker). ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [September 6, 2015, 12:25am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/63 "2015-09-06T00:25:55Z")
A quick one for the programmers out there. As you may know, leap years occur when the year is evenly divisible by 4. That is, unless it’s divisible by 100, in which case there’s no leap year. Except in the case where the year is divisible by 400, where you’ve got a leap year again. Given Y as the year, write a C/C++ expression that computes if you have a leap year in as few characters as possible.I can do it in 24. I’m curious if anyone can beat that. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [September 6, 2015, 5:40am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/64 "2015-09-06T05:40:51Z")
Here’s a straightforward way … [SPOILER]… to do it with 18 keystrokes 0==Y%(Y%100?4:400) NOT a leap-year, if good enough, would be just 15 keystrokes. [/SPOILER] ---
**Author:** ![Mr\_Shine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr_shine/32/464_2.png) [@Mr\_Shine](https://boards.straightdope.com/u/Mr_Shine)\ **Post date:** [September 6, 2015, 8:52am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/65 "2015-09-06T08:52:30Z")
If all numbers were to be written out in full in American English and all spaces were removed, what would be the first odd number alphabetically? 8,018,018,885: Eight billion, eighteen million, eighteen thousand, eight hundred, eighty-five. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 11, 2015, 1:36am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/66 "2015-09-11T01:36:29Z")
It’s either dry, yellow, wooden, or strange. What is it? ---
**Author:** ![Biotop](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/biotop/32/321_2.png) [@Biotop](https://boards.straightdope.com/u/Biotop)\ **Post date:** [September 11, 2015, 1:47am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/67 "2015-09-11T01:47:55Z")
> [@Chronos](#): > > It’s either dry, yellow, wooden, or strange. What is it? Those are the only four possibilities, right? ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [September 11, 2015, 1:50am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/68 "2015-09-11T01:50:56Z")
> [@Mr\_Shine](#): > > If all numbers were to be written out in full in American English and all spaces were removed, what would be the first odd number alphabetically? Hmm: I came up with “eight billion and one”. That is the correct full version of that number: no one would ever say “zero million”, and the “and” is required. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 11, 2015, 2:06am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/69 "2015-09-11T02:06:25Z")
> [@](#): > > Those are the only four possibilities, right? I believe so, yes. ---
**Author:** ![Ulf\_the\_Unwashed](https://avatars.discourse-cdn.com/v4/letter/u/b4bc9f/32.png) [@Ulf\_the\_Unwashed](https://boards.straightdope.com/u/Ulf_the_Unwashed)\ **Post date:** [September 11, 2015, 2:17am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/70 "2015-09-11T02:17:59Z")
> [@Dr.Strangelove](#): > > Hmm: I came up with “eight billion and one”. That is the correct full version of that number: no one would ever say “zero million”, and the “and” is required. In the US, at least, the word “and” is not only not required, it is often considered incorrect. “And” is usually reserved for indicating the decimal point. Thus, seven and three tenths but four thousand eight hundred sixty-six. You may or may not agree with this, and of course people don’t typically say it this way in informal speech, but “eight billion one” rather than “eight billion and one” is pretty much standard in American K-12 math textbooks. –Ulf, math textbook writer ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [September 11, 2015, 3:52am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/71 "2015-09-11T03:52:49Z")
> [@Ulf\_the\_Unwashed](#): > > You may or may not agree with this, and of course people don’t typically say it this way in informal speech, but “eight billion one” rather than “eight billion and one” is pretty much standard in American K-12 math textbooks. Well, I defer to your expertise, but “eight billion one” sounds incredibly awkward to my ears. The thousands seem to be a kind of threshold: “eight thousand one” is fine, but not “eight million one”. ---
**Author:** ![Biotop](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/biotop/32/321_2.png) [@Biotop](https://boards.straightdope.com/u/Biotop)\ **Post date:** [September 11, 2015, 3:56am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/72 "2015-09-11T03:56:23Z")
> [@Chronos](#): > > It’s either dry, yellow, wooden, or strange. What is it? This is going to keep me up tonight. Grr… ---
**Author:** ![Isamu](https://avatars.discourse-cdn.com/v4/letter/i/7c8e57/32.png) [@Isamu](https://boards.straightdope.com/u/Isamu)\ **Post date:** [September 11, 2015, 4:18am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/73 "2015-09-11T04:18:57Z")
> [@Chronos](#): > > It’s either dry, yellow, wooden, or strange. What is it? Stephen Colbert’s journalism. ---
**Author:** ![Isamu](https://avatars.discourse-cdn.com/v4/letter/i/7c8e57/32.png) [@Isamu](https://boards.straightdope.com/u/Isamu)\ **Post date:** [September 11, 2015, 4:38am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/74 "2015-09-11T04:38:23Z")
> [@Chronos](#): > > To form a noun that means a person or thing that does it, you _remove_ -er from the end of it. What is the verb? Does a slob slobber? ---
**Author:** ![Your\_Great\_Darsh\_Face](https://avatars.discourse-cdn.com/v4/letter/y/ac8455/32.png) [@Your\_Great\_Darsh\_Face](https://boards.straightdope.com/u/Your_Great_Darsh_Face)\ **Post date:** [September 11, 2015, 8:30am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/75 "2015-09-11T08:30:21Z")
In the neighbouring Pacific islands known as “North Island” and “South Island”, all the natives of North Island tell the truth all the time, and all the natives of South Island tell lies all the time. As usual, they freely intermingle (on the fishing grounds) and cannot be told apart visually. A visitor on a passing boat meets three natives fishing in their canoes and he says to one of them “What islands are you from?”. The native says “The other two are both from the same island”. He then poses the same question to one of the other two and receives the answer “The other two are both from the same island”. He then poses the same question to the third native, who either replies “The other two are both from the same island” or “The other two are from different islands”. 1. What did the third native actually say? 2. Is it possible to tell where any of the natives are from? ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [September 11, 2015, 10:05am UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/76 "2015-09-11T10:05:30Z")
> [@Your\_Great\_Darsh\_Face](#): > > 1. What did the third native actually say? > 2. Is it possible to tell where any of the natives are from? [spoiler]1) He said they’re from the same island. 2) Nope! There are 8 possibilities starting out: NNN, NNS, NSN, NSS, SNN, SNS, SSN, SSS After the first answer, we can remove 4 inconsistent answers, leaving these: NNN, NSS (these two are where the first guy tells the truth), SNS, SSN (these are where the first guy lies) Interestingly, we get no additional information from the second question. All remaining answers are still consistent. Finally, we still get no information if the guy answers “they’re from the same island.” Still 4 possibilities remaining. But conversely, this means that “they’re from different islands” is totally impossible; there’s no way to make it consistent. Given the consistent answer, each guy could have been from either island. Each guy has a 50/50 shot at being from a given island.[/spoiler] ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 11, 2015, 2:03pm UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/77 "2015-09-11T14:03:59Z")
> [@](#): > > This is going to keep me up tonight. Grr… If it helps, it’s an exclusive or. It’s exactly one of those four. ---
**Author:** ![Biotop](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/biotop/32/321_2.png) [@Biotop](https://boards.straightdope.com/u/Biotop)\ **Post date:** [September 11, 2015, 2:15pm UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/78 "2015-09-11T14:15:15Z")
> [@Chronos](#): > > If it helps, it’s an exclusive or. It’s exactly one of those four. In other words, if it is dry it is not yellow…? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 11, 2015, 7:28pm UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/79 "2015-09-11T19:28:40Z")
Right. ---
**Author:** ![EllisDee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ellisdee/32/4531_2.png) [@EllisDee](https://boards.straightdope.com/u/EllisDee)\ **Post date:** [September 11, 2015, 8:49pm UTC](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546/80 "2015-09-11T20:49:36Z")
> [@TriPolar](#): > > We have to assume that the islanders know no more than we do. They don’t know when the rules went into effect, they don’t remember how they got there, all they know is what is expressed in the riddle. Since they can’t communicate they can’t coordinate, none of them knows what the other knows. So it takes the guru to say something so that they all have to start their reasoning from the same day. I agree with Little Nemo. First, because each and every villager can see at least two other villagers with blue eyes, every villager knows for a fact that every villager can see at least one villager with blue eyes. We know they’re all aware of this because the actual solution (which involves a Guru who adds nothing to the equation) requires them to have knowledge of what the other villagers are aware of. [Previous page](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546.md?page=3) [Next page](https://boards.straightdope.com/t/new-riddles-brain-teasers-needed/729546.md?page=5)