# Brain Teasers **URL:** \ **Category:** The Game Room\ **Created:** [July 26, 2010, 4:05pm UTC](https://boards.straightdope.com/t/brain-teasers/548065 "2010-07-26T16:05:31Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![KennerTheGreat](https://avatars.discourse-cdn.com/v4/letter/k/a8b319/32.png) [@KennerTheGreat](https://boards.straightdope.com/u/KennerTheGreat)\ **Post date:** [July 26, 2010, 4:05pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/1 "2010-07-26T16:05:31Z")
1. The day before yesterday, Johnny was 9 years old. Next year, he’ll be 12. How can this be? 2. After a power surge disrupted all the electronic devices in Brian’s house, he had to go over to Amy’s to find out what time it was. After she told him, Brian walked home and set all of his clocks. Even though Brian didn’t know how long it had taken him to get home, he was able to set his clocks to exactly the right time. How? 3. I was about to leave on a morning flight to Paris when I realized I left my briefcase in my office. I rushed back to get it, but the night watchman said “Do not get on that plane! I had a dream last night that it’s going to crash!” Not wanting to tempt fate, I stayed home. Sure enough, the plane crashed. That evening, I thanked the man for saving my life, then I fired him. Why? 4. Seven men were leaving church together when it started to rain. The six who ran got wet, the seventh, who didn’t stayed dry. How? 5. One day, Tom found himself trapped in a room with two doors. Behind the first door was a room made of thick glass that would magnify the sun’s heat to fry whoever went in. Behind the second door was a fire-breathing dragon that would do the same. How did Tom escape unscathed? 6. Malcolm and Joanna competed in a strange horse race. Whoever’s horse reached the finish line _last_ would be the winner. After waiting a few hours for them to go a few feet, I walked out, called them off their horses, and told them something. Immediately, Malcolm and Joanna jumped up on the horses and rode them as fast as they could to the finish line. I didn’t call off the race, or change the rules. So, what did I tell them? ---
**Author:** ![notfrommensa](https://avatars.discourse-cdn.com/v4/letter/n/f14d63/32.png) [@notfrommensa](https://boards.straightdope.com/u/notfrommensa)\ **Post date:** [July 26, 2010, 4:13pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/2 "2010-07-26T16:13:16Z")
> [@KennerTheGreat](#): > > 1. The day before yesterday, Johnny was 9 years old. Next year, he’ll be 12. How can this be? > > 2. After a power surge disrupted all the electronic devices in Brian’s house, he had to go over to Amy’s to find out what time it was. After she told him, Brian walked home and set all of his clocks. Even though Brian didn’t know how long it had taken him to get home, he was able to set his clocks to exactly the right time. How? > > 3. I was about to leave on a morning flight to Paris when I realized I left my briefcase in my office. I rushed back to get it, but the night watchman said “Do not get on that plane! I had a dream last night that it’s going to crash!” Not wanting to tempt fate, I stayed home. Sure enough, the plane crashed. That evening, I thanked the man for saving my life, then I fired him. Why? > > 4. Seven men were leaving church together when it started to rain. The six who ran got wet, the seventh, who didn’t stayed dry. How? > > 5. One day, Tom found himself trapped in a room with two doors. Behind the first door was a room made of thick glass that would magnify the sun’s heat to fry whoever went in. Behind the second door was a fire-breathing dragon that would do the same. How did Tom escape unscathed? > > 6. Malcolm and Joanna competed in a strange horse race. Whoever’s horse reached the finish line _last_ would be the winner. After waiting a few hours for them to go a few feet, I walked out, called them off their horses, and told them something. Immediately, Malcolm and Joanna jumped up on the horses and rode them as fast as they could to the finish line. I didn’t call off the race, or change the rules. So, what did I tell them? 1. and 3. 2. He added half the time of the round trip to the time at Amy’s house. 3. Watchman was sleeping on the job ---
**Author:** ![notfrommensa](https://avatars.discourse-cdn.com/v4/letter/n/f14d63/32.png) [@notfrommensa](https://boards.straightdope.com/u/notfrommensa)\ **Post date:** [July 26, 2010, 4:16pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/3 "2010-07-26T16:16:17Z")
1. Six men were pallbearers, the 7th was in a casket ---
**Author:** ![Giles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giles/32/60_2.png) [@Giles](https://boards.straightdope.com/u/Giles)\ **Post date:** [July 26, 2010, 4:17pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/4 "2010-07-26T16:17:29Z")
> [@KennerTheGreat](#): > > 1. The day before yesterday, Johnny was 9 years old. Next year, he’ll be 12. How can this be? Today is January 1st. Johnny had his 10th birthday yesterday. ---
**Author:** ![KennerTheGreat](https://avatars.discourse-cdn.com/v4/letter/k/a8b319/32.png) [@KennerTheGreat](https://boards.straightdope.com/u/KennerTheGreat)\ **Post date:** [July 26, 2010, 4:17pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/5 "2010-07-26T16:17:55Z")
**notfrommensa** has 3 and 4 right, not 2, though. ---
**Author:** ![Sr\_Siete](https://avatars.discourse-cdn.com/v4/letter/s/6de8d8/32.png) [@Sr\_Siete](https://boards.straightdope.com/u/Sr_Siete)\ **Post date:** [July 26, 2010, 4:18pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/6 "2010-07-26T16:18:29Z")
[SPOILER]1. Okay, if yesterday was both Johnnys birthdy and the 31st of december… something like that. 1. Amy and Brian live together? 2. Because if he’s the night watchman, what was he doing there in the morning. Actually, that also means he slept during working hours, since he just had the dream. 3. The seventh guy stayed in the church? 4. Not opening any door? Waiting for the night? Opening both doors, staying behind one, frying the dragon? Pick one. 5. Already knew that one, so I won’t say it.[/SPOILER] ---
**Author:** ![notfrommensa](https://avatars.discourse-cdn.com/v4/letter/n/f14d63/32.png) [@notfrommensa](https://boards.straightdope.com/u/notfrommensa)\ **Post date:** [July 26, 2010, 4:18pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/7 "2010-07-26T16:18:55Z")
1. You told them that they could jump on the other’s horse. ---
**Author:** ![Hoopy\_Frood](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hoopy_frood/32/8452_2.png) [@Hoopy\_Frood](https://boards.straightdope.com/u/Hoopy_Frood)\ **Post date:** [July 26, 2010, 4:19pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/8 "2010-07-26T16:19:04Z")
1. Johnny was born on December 31. It is now January 1. He was 9 on December 30 of last year, 10 on December 31 of last year, and is 10 today as well. He will be 11 on December 31 of this year, and 12 on December 31 of next year. 1. He borrowed her watch. 1. He was a night watchman. If he had a dream at night, he was sleeping on the job. (Assuming that it wasn’t his night off.) Note: Heard this one before. 1. He had an umbrella…His car was parked out front…He turned around and went back inside to wait out the storm… 1. Don’t know. Have to think about that one a bit longer. 2. Switch the horse you are riding on. Note: Heard this one before. ---
**Author:** ![Hoopy\_Frood](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hoopy_frood/32/8452_2.png) [@Hoopy\_Frood](https://boards.straightdope.com/u/Hoopy_Frood)\ **Post date:** [July 26, 2010, 4:21pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/9 "2010-07-26T16:21:38Z")
> [@KennerTheGreat](#): > > **notfrommensa** has 3 and 4 right, not 2, though. Yeah, but without more constraints on the problem, I think any of the various answers that have been given for four could be correct. Though notfrommensa’s is the most “lateral” thinking of the bunch. ---
**Author:** ![Giles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giles/32/60_2.png) [@Giles](https://boards.straightdope.com/u/Giles)\ **Post date:** [July 26, 2010, 4:24pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/10 "2010-07-26T16:24:28Z")
> [@Hoopy\_Frood](#): > > 1. Don’t know. Have to think about that one a bit longer. Maybe open both both doors, and hide somewhere until the dragon wanders through both doors and gets fried, then escape through the dragon’s former room. ---
**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:** [July 26, 2010, 4:24pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/11 "2010-07-26T16:24:48Z")
2: He set his watch at Amy’s house, then set the rest of his clocks from his watch 5: He waited for night, then left through the Sun-room 6: They rode each others’ horses And a simpler answer to 4: The seventh man had an umbrella ---
**Author:** ![notfrommensa](https://avatars.discourse-cdn.com/v4/letter/n/f14d63/32.png) [@notfrommensa](https://boards.straightdope.com/u/notfrommensa)\ **Post date:** [July 26, 2010, 4:25pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/12 "2010-07-26T16:25:22Z")
1. He waited until nightfall and left through the room with thick glass ---
**Author:** ![MeanOldLady](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/meanoldlady/32/10737_2.png) [@MeanOldLady](https://boards.straightdope.com/u/MeanOldLady)\ **Post date:** [July 26, 2010, 4:53pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/13 "2010-07-26T16:53:59Z")
> [@Chronos](#): > > 2: He set his watch at Amy’s house, then set the rest of his clocks from his watch If he had a watch, he wouldn’t have needed to go to Amy’s to get the time. > [@](#): > > 5: He waited for night, then left through the Sun-room Of course! This makes more sense than my answer. I was one of those fry the dragon people. ---
**Author:** ![Indistinguishable](https://avatars.discourse-cdn.com/v4/letter/i/90ced4/32.png) [@Indistinguishable](https://boards.straightdope.com/u/Indistinguishable)\ **Post date:** [July 26, 2010, 4:56pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/14 "2010-07-26T16:56:15Z")
> [@MeanOldLady](#): > > If he had a watch, he wouldn’t have needed to go to Amy’s to get the time. What’s more, even if he only borrowed a watch from Amy, he then _would_ know how long it took him to get back home (at least, he would have the ability to know). (I feel people are overly cautious about spoilers in these kinds of threads; if we’re going to have any discussion, it’s silly to have the whole thing hidden away behind spoiler tags. Anyone who wants to avoid spoilers can avoid reading past the OP) ---
**Author:** ![MeanOldLady](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/meanoldlady/32/10737_2.png) [@MeanOldLady](https://boards.straightdope.com/u/MeanOldLady)\ **Post date:** [July 26, 2010, 5:48pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/15 "2010-07-26T17:48:19Z")
I feel the same way, but everyone else spoilered theirs, and I didn’t want to come in a piss on everyone’s parade. ---
**Author:** ![Indistinguishable](https://avatars.discourse-cdn.com/v4/letter/i/90ced4/32.png) [@Indistinguishable](https://boards.straightdope.com/u/Indistinguishable)\ **Post date:** [July 26, 2010, 5:51pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/16 "2010-07-26T17:51:58Z")
Oh, I wasn’t talking about you specifically; I followed suit as well. Just making a general observation in hopes that everyone will soon agree we can stop doing it. ---
**Author:** ![Hoopy\_Frood](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hoopy_frood/32/8452_2.png) [@Hoopy\_Frood](https://boards.straightdope.com/u/Hoopy_Frood)\ **Post date:** [July 26, 2010, 8:12pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/17 "2010-07-26T20:12:21Z")
> [@Indistinguishable](#): > > > [@MeanOldLady](#): > > > > If he had a watch, he wouldn’t have needed to go to Amy’s to get the time. > > What’s more, even if he only borrowed a watch from Amy, he then _would_ know how long it took him to get back home (at least, he would have the ability to know). > > (I feel people are overly cautious about spoilers in these kinds of threads; if we’re going to have any discussion, it’s silly to have the whole thing hidden away behind spoiler tags. Anyone who wants to avoid spoilers can avoid reading past the OP) I know that. But the puzzle doesn’t say he updated his clocks immediately upon coming home. Maybe she told him the time when he arrived, and then said, here borrow my watch. And they sat around and had some tea. He didn’t bother checking the time when he left, because at that point it really didn’t matter anymore. Heck, I would have just looked at my cell phone. But I was intentionally coming up with other answers than the one that’s probably being looked for, which is he sets his clocks to some arbitrary time before he leaves (12:00 works well). And then walks to Amy’s, gets the time, and walks back. Adding half the time change on his clocks to the time Amy gave him should get his clocks close enough for government work. Of course, this assumes he doesn’t get delayed in either direction for any reason. Heck, even if he the days before cellphones, he could just call information on a landline for the time if he was that desperate. Or turn on the TV/radio. Walking all the way to a friend’s place seems like a lot of effort to just find out what time it is. ---
**Author:** ![Hoopy\_Frood](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hoopy_frood/32/8452_2.png) [@Hoopy\_Frood](https://boards.straightdope.com/u/Hoopy_Frood)\ **Post date:** [July 26, 2010, 8:14pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/18 "2010-07-26T20:14:28Z")
Oh, and I figured out 5. Pretty obvious once you think about it. (Reminds me of the whole black car on a black street with no lights on thing, but in reverse.) ---
**Author:** ![Tom\_Scud](https://avatars.discourse-cdn.com/v4/letter/t/f08c70/32.png) [@Tom\_Scud](https://boards.straightdope.com/u/Tom_Scud)\ **Post date:** [July 26, 2010, 8:25pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/19 "2010-07-26T20:25:30Z")
> [@KennerTheGreat](#): > > 1. The day before yesterday, Johnny was 9 years old. Next year, he’ll be 12. How can this be? A different answer than others have given: Johnny lives on a planet where the length of the day and the year are equal. ---
**Author:** ![Attack\_from\_the\_3rd\_dimension](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@Attack\_from\_the\_3rd\_dimension](https://boards.straightdope.com/u/Attack_from_the_3rd_dimension)\ **Post date:** [July 26, 2010, 8:36pm UTC](https://boards.straightdope.com/t/brain-teasers/548065/20 "2010-07-26T20:36:49Z")
> [@KennerTheGreat](#): > > 1. Seven men were leaving church together when it started to rain. The six who ran got wet, the seventh, who didn’t stayed dry. How? They _were_ leaving. Number seven decided not to leave and and stayed dry. [Next page](https://boards.straightdope.com/t/brain-teasers/548065.md?page=2)