May 2008

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• logical recreations

  [006] Solution

  05.22.08 | Permalink | 1 Comment

  This is a solution for problem What Happens if an Irresistible Cannonball Hits an Immovable Post?
  The given conditions of the problem are logically contradictory. It is logically impossible that there can exist both an irresistible cannonball and an immovable post. If an irresistible cannonball should exist, then by definition it would knock over any post [...]

• logical recreations

  [006] What Happens if an Irresistible Cannonball Hits an Immovable Post?

  05.19.08 | Permalink | 2 Comments

  This is another problem from my childhood which I like very much. By an irresistible cannonball we shall mean a cannonball which knocks over everything in its way. By an immovable post we shall mean a post which cannot be knocked over by anything. So what happens if an irresistible cannonball hits an immovable post?
  Before [...]

• logical recreations

  [005] Whose picture? v.2

  05.19.08 | Permalink | 1 Comment

  Suppose, in the above situation, the man had instead answered: ‘Brothers and sisters have I none, but this man’s son is my father’s son.’ Now whose picture is the man looking at?

• logical recreations

  Whose picture Am I Looking At?

  05.19.08 | Permalink | Comment?

  We will start with some good old-time puzzles which have amused many a generation. Some of these, many of you already know, but even for those in the know, I have a few new wrinkles.

  This puzzle was extremely popular during my childhood, but today it seems less widely known. The remarkable thing about this problem [...]

• logical recreations

  The Joke Was on Me

  05.19.08 | Permalink | Comment?

  A fellow graduate student of mine at the University of Chicago had two brothers, aged six and eight. I was a frequent visitor to their house and often did tricks for the children. One day I came and said,’ I have a trick in which I could turn you both into lions.’ To my surprise, [...]

• logical recreations, riddles

  Was I Lying?

  05.19.08 | Permalink | Comment?

  A related incident occurred many years later when I was a graduate student at the University of Chicago. I decided to have a job as a seller. I applied to a vacuum cleaner company and had to take an aptitude test. One of the questions was, ‘Do you object to telling a little lie every [...]

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