# Short mind boggling questions

1. Mar 22, 2012

### dpa

hi all,
i want you to post best mind boggling/twisting questions you know of.
Thanks
dpa

2. Mar 22, 2012

### Staff: Mentor

Why is it that sometimes my pain pills work one day and not the next for the same symptom?

Will you be answering our questions?

3. Mar 22, 2012

### Ryan_m_b

Staff Emeritus
By what stretch of the imagination is this "art"?

4. Mar 22, 2012

### dpa

sorry but i was not expecting humour.
You know, the problem solving kinda.
And i am not going to answer on forum. We can think on our own.
Its so simple. The date of pills expired exactly after you took them the previous day. It's as simple as that.

5. Mar 22, 2012

### DragonPetter

A player kicks a ball and it comes back to him without bouncing off of anything else, how is this possible?

6. Mar 22, 2012

### Ryan_m_b

Staff Emeritus
He kicks it up

7. Mar 22, 2012

### DragonPetter

No, he kicks it into a hurricane that blows it back at him.

8. Mar 22, 2012

### lisab

Staff Emeritus
One person's boggle line is different from another's. Most PFers would find this question pretty easy, I think:

Alice leaves her house and walks north for 5 km. Then she turns and walks west for 5 km. Then she turns south and walks 5 km, and is back at her house, where she started. How is this possible?

9. Mar 22, 2012

### Ryan_m_b

Staff Emeritus
Something to do with this?

10. Mar 22, 2012

### Q_Goest

I bet Alice's toes are frozen.

~~~

Here's an oldie I really love: You're in a room with 2 doors and 2 guards. One of the doors leads to freedom, the other to death, you don't know which is which. One of the guards always tells the truth the always lies but you don't know which guard is which.

You are allowed to ask one of the guards one question to gain your freedom. What do you ask?

11. Mar 22, 2012

### humanino

Lemme fix that for you

12. Mar 22, 2012

### DragonPetter

You ask one guard what the other guard would say if you asked him which door leads to freedom.

13. Mar 22, 2012

### zooxanthellae

Think about the set of all sets that are not members of themselves!

14. Mar 22, 2012

### lisab

Staff Emeritus
nice

15. Mar 22, 2012

### dpa

well if eons later that is the only piece of digital work that survives and everything even our way of sleeping changes, then this would be one of the most valued art piece.

16. Mar 22, 2012

### Staff: Mentor

Woule it be art or just a picture of a messy bedroom? I believe it would be considered the latter.

17. Mar 22, 2012

### dpa

you see you consider a broken rustic chalice or ancient vase as work of art and preserve in a museum and even pay millions.

Yeah, its all about how you define art as!

18. Mar 22, 2012

### Staff: Mentor

It's not so much art as an historical piece.

19. Mar 22, 2012

### QuarkCharmer

I came up with two interesting solutions, and was working on a third at the bottom of this page that micromass might be interested in reading:

I'll post a link to the image so I don't spoil it:
http://i43.tinypic.com/ibawhs.jpg

20. Mar 22, 2012

### lisab

Staff Emeritus
That made me lol! I love it!

Nice kitty

21. Mar 22, 2012

### humanino

You can turn around several times, so there are actually infinitely many solutions of your type (1)

Type (2) is new to me however, and pretty neat

22. Mar 22, 2012

### QuarkCharmer

That's why the "equator" is there. It's really just a line describing the domain of alice's house.

A short "mind boggling" problem with a "not short" answer:
http://www.mathpages.com/home/kmath668/kmath668_files/image001.gif [Broken]
Infinite grid of resistors with resistance R. Find the resistance between two adjacent nodes.

I tried it for a long time, refusing to look for a solution. I finally caved though :(

(If you want to try it yourself, all you need to know is that resistors in series add up to an equivalent resistance, and resistors in parallel are equivalent by: $\frac{1}{R_{eq}} = \frac{1}{R_{1}}+\frac{1}{R_{2}}+\frac{1}{R_{3}}+...+\frac{1}{R_{n}}$ )

Last edited by a moderator: May 5, 2017
23. Mar 23, 2012

### Jimmy Snyder

If a chicken and a half can lay an egg and a half in a day and a half, then how long will it take for a cockroach to kick all the seeds out of a cucumber?

24. Mar 23, 2012

### Ryan_m_b

Staff Emeritus
Exactly Evo. The fact that something is a historical artefact does not automatically make it art. When I visit museums to see ancient tools it is not because I want to go and see something artistic. Even if I go to see ancient art that is far more due to historical curiosity than artistic. If someone now made a cave painting it wouldn't interest me, what interests me is the historical significance.

25. Mar 23, 2012

### Borg

Divine intervention.