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A brain teaser is a form of puzzle that involves a lot of thinking (mental/cognitive activity). Normally, this includes thinking in conventional ways with given constraints in mind; sometimes, it also involves lateral thinking. Logic puzzles and riddles are specific types of brain teasers. Brain Teasers often have something to do with logic or math. Others don't, but either way, they are good for your mind, and can help you understand some things better. Image File history File links Broom_icon. ...
A puzzle is a problem or enigma that challenges ingenuity. ...
A logic puzzle is a puzzle deriving from the mathematics field of deduction. ...
A riddle is a statement or question having a double or veiled meaning, put forth as a puzzle to be solved. ...
Example:
- Q: If three hens lay three eggs in three days, how many eggs does a hen lay in one day?
- A1: One third. (Note: 3 hens = 3 eggs / 3 days → 3 hens = (3 / 3) (eggs / days) → 1 hen = (1 / 3) (egg / days))
- A2: Zero or one (it's hard to lay a third of an egg; unless it's a very long labour).
It is easy for people to argue about the answers of many brain teasers; in the given example with hens, one might claim that all the eggs in the question were laid in the first day, so the answer would be one, or comment that it is rare for a hen to lay a fraction of an egg. This article or section does not adequately cite its references or sources. ...
In most birds and reptiles, an egg (Latin ovum) is the zygote, resulting from fertilization of the ovum. ...
Look up day in Wiktionary, the free dictionary. ...
The difficulty of many brain teasers relies on a certain degree of fallacy in human intuitiveness. This is most common in brain teasers relating to conditional probability, because the casual human mind tends to consider absolute probability instead. As a result, a great number of controversial discussions emerge from such problems, the most famous probably being the Monty Hall problem. Another (simpler) example of such a brain teaser is given here: This article defines some terms which characterize probability distributions of two or more variables. ...
In search of a new car, the player picks door 1. ...
- If we encounter someone with two children, given that at least one of them is a son, what is the probability that the other is also a son?
(Of course, for the purpose of simplicity, we will disregard hermaphrodites and assume that boys and girls are born with equal probability.) The common intuitive way of thinking is that the births of the two children are independent of each other, and so the answer must be the absolute probability of one child being a boy, 1/2. However, the correct answer is 1/3 as shown by the following argument: The 1st-century BC sculpture The Reclining Hermaphrodite, in the Museo Nazionale Romano, Palazzo Massimo Alle Terme in Rome In zoology and botany, a hermaphrodite is an organism that possesses both male and female sex organs during its life. ...
- For a single birth, there are two possibilities (a boy or a girl) with equal probability.
- Therefore, for two births, there are four possibilities: 1) two boys, 2) two girls, 3) first a boy, then a girl, and 4) first a girl, then a boy; all of them have equal probability.
- We are given that one of the children is a boy. Thus, only one of the four possibilities -- two daughters -- is eliminated. Three possibilities with equal probabilities (1/3) remain.
- Out of those three, only one -- two sons -- is what we are looking for. Hence, the answer is 1/3.
Alternatively, one can see that in any sample of families with two children, 3/4 of them will have at least one son, and 1/4 will have two sons. The probability is thus (1/4)/(3/4) = 1/3. The common intuitive way of thinking is equivalent to considering families in which a particular child (e.g. the first-born, or the one that comes first in the alphabet, etc.) is a son (which is only 1/2 of the sample, not 3/4) and seeing how many of them have two sons.
One might formulate the above as
- If someone has two children, and one of them is a son, what is the probability that the other is also a son?
but that would be (more) ambiguous, since it could mean that we chose a person at random, and learnt that at least one of their two children was a son (in which case we get 1/3), or it could mean that we chose a person at random, and met one of their children, which turned out to be a son. This would then be a particular child, so the probability of the other being a son is 1/2.
The difference lies in the specific choice of words: The first example is considering the probability of a family having two sons in a row, if at least one of them is a son already (as shown in the proof). The second example might be understood to only ask for the sex of the second child, which is, given an even distribution of children born to each gender, one half or 1/2 either way.
See also
This is a partial list of notable puzzle-based computer games and video games, sorted by general category. ...
A board game is a game played with counters or pieces that are placed on, removed from, or moved across a board (a premarked surface, usually specific to that game). ...
A logic puzzle is a puzzle deriving from the mathematics field of deduction. ...
A mathematical problem is a problem that can be solved with the help of mathematics. ...
Mathematical games include many topics which are a part of recreational mathematics, but can also cover topics such as the mathematics of games, and playing games with mathematics. ...
Mensa International is the largest, oldest, and best-known high-IQ society in the world. ...
A game of mental skill (sometimes called a mind sport) is a game where training of muscles and skill in controlling them offers insignificant advantage, and mental abilities are paramount. ...
A puzzle is a problem or enigma that challenges ingenuity. ...
A riddle is a statement or question having a double or veiled meaning, put forth as a puzzle to be solved. ...
External links - Brain Teasers at the Open Directory Project (suggest site) – An active listing of links to brain teasers.
- Watch and download a logic game
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