Brain Teasers and Puzzles

If you're in a box in a house are you in a house or a box??

Earlier in the year as a means of procrastination, myself and some friends semi-participated in a puzzle competition called CiSRA, which is run each year by a team from Canon (website found here). On about the third day, they released a puzzle listed as 'hard' that I decided to take on and try solve myself. All in all, it took about a week of wanting to throw my computer out the window until I had an epiphany of sorts and managed to get it out. Despite the mind melt it induced, I actually have come to adore this particular puzzle and thought I might share it with the wider community. The puzzle may be downloaded as a PDF from here. Alternatively, this is the puz…

I made it P=0 T+E = 8 Q+O = 10 With the given clues, find the sum of the letters T R E E. (Each letter represents a number if you didn't know already) Have fun!

I came up with a clever riddle that is based on Wes Craven's Wishmaster, so far nobody's been able to guess the answer; although I'm sre there are solutions which I haven't thought of. One day a woman finds an ancient fire opal, out of which emerges an evil demon called the djinn, who demands that she make three wishes. Upon the granting of the third wish, the djinn's brethren shall be released from hell to wreak havoc upon the Earth. He tells her that he must grant anything she wishes; limited only by her imagination. Frantic to save the Earth, the woman's first wish is that the djinn should kill itself; thus the djinn conjures a pistol and shoots itself in the head,…

Suppose two snails are having a race. They both start out at a speed of 1m per day, but they both will slow down: After every hour, snail A reduces its speed by half. After every milliimeter covered, B reduces its speed by half. If the race is 1m long, who would win?

I recently saw an astronomy picture that had the moon in it and a nebula which looked as big as the moon. I can't remember where I saw it... does anyone know if there are nebulas that actually look as big as the moon from Earth? And how far away would such a nebula be? Here's my puzzle: Suppose you had a nebula that looks as big as the moon. Suppose that this imaginary nebula happens to be as dense as the moon. Which would have a stronger gravitational pull on us? You can assume the nebula is spherical and whatever distance away you want. Say, 100 light years.

Just a fun project to find the truly devious and unorthodox thinkers. The challenge is to provide a step by step ultimate revenge plot. Ideas may be published as part of a book. There are rules 1) the scenario cannot be an elaborate murder plot no physical harm can befall the victim. 2)I.D. forgery or credit fraud are out however forgery of letterheads etc. is acceptable. 3)vandalism and destruction of personal property is not permitted 4) there are no other rules just be original I think the rules make that an obvious requirement. The person you are seeking vengeance against has taken everything from you, you were incarcerated on false testimony from this per…

Part 1: About the same time that I discovered how to modify a function as to only affect a single output, I also discovered a way to produce the following sequence using only elementary operators {+, -, *, / and ^}: {1, 1, 2, 2, 3, 3, 4, 4, etc...} I do realize that a solution could be found using the floor and ceiling operators, but that will not be accepted for the answer. As in my first challenge, you are only allowed to use addition, subtraction, multiplication, division and exponents. No other operators are allowed. Also the function is restricted to the set of integers. Because the domain can be shifted to start with whatever input you choose, I will…

I know most of you have seen this problem at one point in time or another. The question normally wants you to count all of the triangles you see in the image. This challenge is not concerned with just counting triangles, but wants the equation which predicts the total number of triangles given [math]n[/math] number of rows. The equation uses elementary operators and I will not accept a solution that is based on floor / ceiling, modular arithmetic, or piecewise functions / two part solutions. You must provide a single function which predicts the count of triangles given any number of rows. As with all of my challenges, I will give reputation to the person who can …

This puzzle deals with a variation of Hilbert's infinite hotel... http://en.wikipedia.org/wiki/Hilbert_hotel. In the simplest example, the hotel can be full but you can make room for another guest by moving every guest one room over. By induction, you can repeat this infinitely many times, and accommodate an infinite number of new guests. You can also accommodate a countably infinite number of guests all at once by moving every guest in room n to room 2n, freeing up all the infinitely many odd numbered rooms. All the above stuff should be clear to anyone familiar with the paradox. Variation: A hotel with an infinite number of rooms can take up a…

Hi all, I'm new to these forums, but I absolutely love riddles. I don't know if this one has been posted, but I love it and it took me ages to figure out. I'm sure someone can figure it out much more quickly. There are 12 balls. All of them weigh exactly the same except for one. That odd ball out is either heavier or lighter than the rest. You have a balance scale (which can tell you which side has the heavier items) and are permitted to make only 3 weighings (i.e. make comparisons between any two sets of balls at most 3 times). How do you weigh the balls so you that can figure out (with 100% certainty) which ball is different and whether it is heavier or lighter …

If the hour and minute hands are equidistant from the 6 hour, what is the exact time?

who in your opinion would win?

What gets wetter the more you dry? A Towel.

there was alge placed in a lake at 12am the alge doubles every second the lake was full at 12:00pm. when was the lake half full?

While hiking through the mountains, you get lost and end up in a village, population 99. You only have $200 left. Everyone is greedy, so they won't do anything for free. The majority of the townsfolk are also honest, but some are troublemakers. You need to hire one of the honest citizens as your guide home, which will cost $100. But first you need to nd one that is honest. For $1, you can ask any villager if another villager is honest. If you ask an honest villager, they tell the truth. If you ask a troublemakers, they might say anything. (The villagers don't understand other kinds of questions.) Come up with a way to nd an honest villager for sure, and with enough money…

As far as I know, it is illegal to receive an illegal attachment or email in america. So, could one email something illegal to the white house? Even better, could I write something, copyright it, and then have my sister email it, and then only prosecute the recipient? Note: I'm not by any means suggesting that someone do this, I'm just wondering if it would, theoretically, work.

What becomes wetter as it dries?

Suppose you want to prove the statement "All crows are black". You can't do it logically, it has to be done empirically. One way is to go out and look at every crow and note its color. Every black crow would be a confirming instance of the statement, and increases (however slightly) the likelihood of the statement being true. The more black crows you see, the more likely the statement is to be true. The statement could only be proven if you could examine every crow and find that each is black. Now consider this: The statement "all crows are black" is the logical equivalent of "all non-black objects are not-crows". So if you go out and see a purple cow, that is a…

Greetings learned person! I bring to you a problem of condensation. We have a 5000 sq ft basement with a tiled concrete floor. Next we introduce 25-34 people and have them enjoy the sport of table tennis for 4-5 hours. It is Spring and the relative humidity is high. The players perspire. Humidity increases in the basement. There are two bucket collecting dehumidifiers running non stop, and one small airconditioner running. After 2-3 hours the floor begins to draw moisture out of the air. The condensation makes the floor slick, and players cannot play. The condensation starts where the floor meets the exterior walls and slowly moves toward the center o…

I found an old paper when I was cleaning my room. It belonged to my friend and was by mistake in my house. I wanted to know the answers of these questions. I would post them one by one. Problem 1 A man was sitting in a room, reading a book, when his wife entered the room and switched off the light. Although this occured at night, and the room was now pitch dark, the man continued reading as though nothing had happened. How could he do this?

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Okay so. How long would a year be in seconds if a second were shortened to 0.864 of it's original length? The original second is named the standard second (ss) and the new second is named the new second (ns). -------------------------------------------------------------------------------- Facts which may or may not be helpful to you: There are exactly 86,400 standard seconds in a standard day. There are approximately 31,556,952 standard seconds in a year. From Wikipedia: "Under the International System of Units (via the International Committee for Weights and Measures, or CIPM), since 1967 the second has been defined as the duration of 9,192,631,770…

While this is essentially not a puzzle, I think it presents an interesting subject for sciency people. It's called the Pinocchio Paradox, and is based on the idea that when Pinocchio tells a lie, his nose grows longer (see the attachment). Using the following definition of "paradox" from the American Heritage Dictionary: " An assertion that is essentially self-contradictory, though based on a valid deduction from acceptable premises" is this actually a paradox? Now, discuss.

I was trying to calculate the speed of something over a small distance and convert it into mph. Turns out I forgot how. Anyways as I was attempting to remember I came up with this: If 360,000 jet cars travel across a 3.4 mile long bride in 1 hour, what is the average speed for each jet car in mph?