BrainDen.com - Brain Teasers

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## Popular Content

Showing content with the highest reputation since 07/16/13 in all areas

1. 2 points

## A Simple Riddle

In our circles you may find A laugh, a wink, a grin But pressure us we'll likely snap And send away our kin. We don't do much, we go to pot Such simple ones are we But with your hand we take command Or from you we will flee.
2. 2 points

## Folding paper

Agree. When I hit the send button, I realized my thinking was too simple. But instead of deleting my post (moderator privilege) I left it to take its licks.
3. 2 points

## Simulating an n-sided die with two coins

Say we want to simulate an N sided die.
4. 2 points

5. 2 points

## Upside Down Cake

(This puzzle is from a blog called By Way Of Contradiction.) Imagine you have a circular cake, that is frosted on the top. You cut a d degree slice out of it, and then put it back, but rotated so that it is upside down. Now, d degrees of the cake have frosting on the bottom, while 360 minus d degrees have frosting on the top. Rotate the cake d degrees, take the next slice, and put it upside down. Now, assuming the d is less than 180, 2d degrees of the cake will have frosting on the bottom. If d is 60 degrees, then after you repeat this procedure, flipping a single slice and rotating 6 times, all the frosting will be on the bottom. If you repeat the procedure 12 times, all of the frosting will be back on the top of the cake. For what values of d does the cake eventually get back to having all the frosting on the top?
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## I swear:

I swear: 1) To strangle the next person who uses 'suicide' as a verb. 2) That if I offended or hurt you in any way, I didn't mean it. 3) That I'll stop procrastinating. Tomorrow. Add whatever you swear.
9. 2 points

## Human origin" according to my own theory"

Personally, the original reason I believed in God is that an adult told me he existed when I was little and, being little, I took their word. But over time, I've listened to people talk about their experiences with God and seen it with others. I think I've seen Him get me through a lot of stuff the past few years that I don't think I'd have been able to make it through alone. You could say that I got through them because I worked hard, or just because believing in a higher power has some effect psychologically, or that there were coincidences involved, but when I put it all together, those reasons just don't work for me. But if I had to give just one reason that I believe God is real, it would be that He told me so. Audibly.
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11. 2 points

## Crazy People

eq ( 1 ) Study = not failed eq. ( 2 ) not study = failed add eq ( 1 ) & ( 2 ) study + not study = fail + not fail study ( 1 + not ) = fail ( 1 + not ) study = fail Then why should we study??
12. 2 points

## Blonde Jokes

this one is pretty cute! Blonde v.s. Lawyer a lawyer sitting on a plane next to a Blonde want to pass some time and turns to her and says, "how about a trivia game, if i ask you a question and you get it right I'll pay you 10 dollars, and if you get it wrong you pay me 1 dollar. then you ask me a question, with the same conditions." blonde says, "no thanks, I'm reading a book." the lawyer says, "okay how about this, 20 dollars for getting right for you, and 20 dollars for getting wrong for me." the blonde rolls her eyes and says fine. the lawyer asks, "whats the distance from the earth to the sun?" the blonde hands him a dollar. then the blonde asks him, "what goes uphill with 3 legs and down hill with 4?" the lawyer blinks for a second and says " i have no idea, i guess you win that round." then hands her 20. "okay my turn again, i am curious, what does go up hill with three legs and down hill with 4?" the blonde hands him another dollar.
13. 2 points

## One Up Me

What happens in quantum statistical thermodynamics stays in quantum statistical thermodynamics...b/c no one else cares.
14. 2 points

## One Up Me

Out of the frying pan and on to the floor. Back into the frying pan, let hope none of the guests saw.
15. 2 points

## Crocodile Sophism

I would think that the only way to make ANY sense of the situation is for the woman to repeat back to the croc EXACTLY what he said to HER: "If I guess right, you'll give my baby back, if I dont, you'll eat him. That's what you'll do to him." He'd have to return the baby, because she's CORRECT NO MATTER WHAT. Eh? hehehe
16. 1 point

## Walking, running, driving, waiting

I'll accept it but I was thinking more like ....
17. 1 point

## The Pebbles

We are in a TV game. We have 8 same looking boxes, each of which has 2 pebbles. Each pebble could be either precious or not precious. We choose a box and the host, without looking inside the box, pulls out a pebble. It comes out to be precious. The TV host then declares that we have exactly 50% chance that the 2nd pebble inside the box is precious, too. If we know that, in the beginning of the game, the count of precious pebbles is no less than the count of not precious pebbles, which of the statements MUST be true? We assume that the TV host knows the pebbles distribution in the boxes - in what amount of boxes the precious pebbles are 0,1 or 2. The TV host, however, doesn't know the kind of pebbles in each specific box, as he himself doesn't differ the boxes from one another. 1. If we swapped the boxes, we would have higher chance of picking up precious pebble next. 2. If we swapped the boxes, we would have same chance of picking up precious pebble next. 3. If we swapped the boxes, we would have lower chance of picking up precious pebble next. 4. In the beggining of the game, there've been exactly 2 boxes with 2 precious pebbles each. 5. In the beginning of the game, half the boxes have had 1 precious and 1 not precious pebble. 6. In the beginning of the game, the precious and not precious pebbles have been equal in count. 7. In the beginning of the game, the amount of boxes with 2 precious pebbles is equal to the amount of boxes with 2 not precious pebbles. 8. The TV host has gone wrong. There's no way that there's 50% chance for 2nd precious pebble in our box, as there is unequal amount of pebbles left in the game. 9. None of the above must be true.
18. 1 point

## Smallest Grid to Fit 1 2 3 4 5 6 7 8 9 0

so far just 2
19. 1 point

## Burning Riddle

But off Course! : )
20. 1 point

## Mouse & Cheese Cube

Hopefully this one has not appeared before... Suppose 27 identical cubical chunks of cheese are piled together to form a cubical stack, as illustrated below. What is the maximum number of these cheese chunks through which a mouse of negligible size could munch before exiting the stack, assuming that the mouse always travels along the grid of 27 straight lines that pass through the centers of the chunks parallel or perpendicular to their sides, always makes a 90 degree turn at the center of each chunk it enters, and never enters any chunk more than once?
21. 1 point

## Thank goodness, no remainder is chasing me

Ten years ago I called attention to a number that when divided by a single integer p it left a remainder of p-1. (Help, a remainder is chasing me) Here is a chance to construct a nine-digit number, a permutation of { 1 2 3 4 5 6 7 8 9 } that has no remainders, sort of. The task is to permute { 1 2 3 4 5 6 7 8 9 } to create a number whose first n digits is a multiple of n for any single-digit n. For example, consider 123654987. Its first 2 digits (12) are divisible by 2. It's first 5 digits (12365) are divisible by 5. However this is not a solution, since 1236549 is not a multiple of 7.
22. 1 point

## Westworld Mafia Signups

Signups: 1. Gavinksong2. Flamebirde3. Nana774. plasmid5. phil18826. bonanova 7. aura8.9. 10.11.12 I've just moved, to Ohio, from NY and drowning in the details of it. Reluctant to pledging my attention here. But, I'll give it a shot ... Should be able to check in at least daily.
23. 1 point

24. 1 point

## A Nine Puzzle

Use three 9's and arrange them using the mathematical signs to form the number one.
25. 1 point

## Re-ROLLO

TRICK
26. 1 point

I believe you replace the ? with digits.
27. 1 point

## Connect the Dots

and a Spoiler for some additional thoughts:
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29. 1 point

## Weighing Bells

Part A ) I can identify weights of all bells in 6 weighings or less. I don't know what B ) means. In what follows, "L" means "Low", "H" means "High". The results of a weighing are always Equal (all three pans equal weight), LL (two Low pans are equal, third is lighter), L (one Low pan is lowest, other two pans are lighter and indeterminate) Case 1b: Case 1c:
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33. 1 point

## Equilateral Triangles: Horizontal = Slant

You understood the question perfectly. I guess this one was too easy
34. 1 point

## I'm not a skier

hello plasmid - happy new year. as always, have really been enjoying this latest I'm not a. had a different thought with each stanza when first read.
35. 1 point

## Weighing machines

I started working out a similar solution for 10, but didn't have enough time to finish it yet. I'm trying to do it in 3 weighings using a digital scale, but so far, looks like it will require 4. Maybe a combination of digital/balance could be optimal. Is it allowed?
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39. 1 point

## Wrist Watch

Does "when its 11:11:11 pm" refer to the actual time, or to the position of the hands? PM as in real time because when its 11:11:11 pm actual time, the 3 hands must be on "specific" angles..It can not be 2:56:11 or 11:11:10 or 2:10:56 actual time. The hands' positions on 9:05:25am is same as 9:05:25pm (actual time) so the are actually around 2hrs,6min to figure this out..
40. 1 point

41. 1 point

## Symbolic Gesture

Mu sigmed it up quite nicely Wilson ie with the lambda comment .
42. 1 point

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44. 1 point

You rang?
45. 1 point

## Chase on an endless road, continued

Caught again, your friend concedes that you are the supreme runner. Maybe it's not a coincidence that your profile pic is an ostrich
46. 1 point

This also reminds me of this (Concave and Convex by MC Escher):
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48. 1 point

49. 1 point

## The Bible

noah took onto the ark: Genesis 7: 2, where God tells Noah: 'Of every clean beast thou shalt take to thee by sevens, the male and his female: and of the beasts that are not clean by two, the male and his female' so he either took 7 males and 7 females of the clean ones, or just seven in total, depending on how you understand the sentence. the idea of two by two is only relevant to unclean animals (like pigs, camels, eels, snails etc etc). gotta love QI
50. 1 point

I don't quite understand the fascination with 'paradoxes' of this sort, which basically come down to which of the two statements are true, if any. I am blue. I am red. Am I blue or red? Maybe I'm green. Doesn't matter, both cannot be true. The truth is on the other side. The other side holds no truths. Or is that just it? We enjoy 'trapping' the mind in a room with mirrors on both the wall we are facing and the wall directly behind, and looking at the infinite reflections that result? I just don't get it. Can someone tell me what I am missing? I am reminded of the "bullet that pierces all vs. armour that cannot be pierced" contradiction. Similar situation, both just cannot exist. One is right, the other is wrong, or maybe both are wrong, but the contradictory elements cannot both be right.
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