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Interesting logic problems

Discussion in 'Fred's House of Pancakes' started by eagle33199, Mar 11, 2010.

  1. eagle33199

    eagle33199 Platinum Member

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    Rules for the thread... Answer the problem posted (correctly, maybe show the logic that lead to the answer), and post a new problem! Any sort of logic problem goes... but the solution has to have its roots in logic. And since i'm making the thread, i get to start :)

    If:
    2 + 3 = 10
    7 + 2 = 63
    6 + 5 = 66
    8 + 4 = 96


    Then:
    9 + 7 = ????


     
  2. rpatterman

    rpatterman Thinking Progressive

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  3. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    Solution:
    A + B * A = answer


    Therefore:
    1 + 1 = 1
    2 + 2 = 8
    3 + 3 = 18

    Mine (I like verbal logic problems):
    I'm driving down the road. The moon's not up but it wouldn't matter since it's cloudy. There's a blackout and none of the street lights are lit. By sheer bad luck, my headlights are burned out. In short, there is no illumination from anywhere. Not only am I able to drive down the street when when a black dog walks into the street I am able to stop without hitting it. How did I see the dog?
     
  4. Tamyu

    Tamyu New Member

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    9 + 7 = 144 :D

    Here is mine;

    If
    5 * 6 = 570
    6 * 7 = 1218
    7 * 8 = 2296
    8 * 9 = 3960

    Then
    9 * 10 = ????


    eta; Too bad I put my own and was too late to be the first answer... *sigh*

    It is daytime? :D
     
  5. rpatterman

    rpatterman Thinking Progressive

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    Well you never said it was night time, but you did say "there is no illumination from anywhere". Sunlight even on a cloudy day would be "illumination". Since vision requires illumination, and there is "no illumination", you did not "see" the dog.
     
  6. eagle33199

    eagle33199 Platinum Member

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    Just because it was there... 6390 :)

    I hate verbal logic problems... but that's what i get for starting this thread :) I'm going to guess... since it's apparently cloudy enough to stop all light, it's also storming - there's enough lightning to keep going straight, and one flash briefly illuminated the dog. If i'm right, i've got a verbal problem ready for you :)
     
  7. airportkid

    airportkid Will Fly For Food

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    This rules out daylight, lightning, flashlights or self-illumination, such as Superman's X-Rays, if you were Superman. Ergo, you never saw the dog. It was Chuck Norris's dog, and Chuck Norris doesn't need illumination to see. He stepped out and stopped your car just in time with a karate kick.
     
  8. hyo silver

    hyo silver Awaaaaay

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    Maybe Tony's car has a proximity detector and it stopped itself. Does infra-red count as 'illumination'?

    Or maybe it was a vampire dog with glowing eyes.

    But never mind the dog - how did he drive down the street without seeing where he was going? ;)
     
  9. airportkid

    airportkid Will Fly For Food

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    Two mathemeticians were in a bar celebrating the publication of their joint paper "Practical Applications Involving Utilization of Large Values of 1 for Tax, Bank and Other Non-Comformative Accounting". As they sipped their drinks one of them idly maneuvered some loose toothpicks around on the bar top.
    "Look at that!" he suddenly exclaimed. "With just four toothpicks I've represented a number more than 5 times bigger than the world's wealthiest man's net worth!"
    "Tsk," his partner scoffed, finishing her olive. "That's nothing. Here." She reached over and rearranged one toothpick, took the olive pit out of her mouth and placed it in the new arrangement. "There," she said, "is a number larger than the number of electrons in the known universe!"

    What were the two arrangements of the four toothpicks (and olive pit in the second arrangement)? The toothpicks were whole, neither broken nor deformed.
     
  10. daniel

    daniel Cat Lovers Against the Bomb

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    In Tony's problem, the only answer I can think of is that his car was equipped with sonar, and it signals the driver using sound. Otherwise, daylight, lightning, luminescent eyes, are all forms of illumination.

    (But I suspect that Tony was thinking "artificial illumination" and wanted "daytime" as the answer.)

    In the case of the toothpicks, I can only think that the guy wrote what amounted to 11 to the 11th power. The gal could have used the olive pit as a zero and made 11 to the 110th power, but that would not have involved moving a toothpick.
     
  11. airportkid

    airportkid Will Fly For Food

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    I may have to accept that as an answer, although relative to the length of a toothpick an olive pit's size is closer to something other than a zero (think punctuation), and thus does require shifting a toothpick to make sense. 11 to the 110th is a bigger number than the number of electrons counted so far in the universe (not one by one, at least not by anyone we know), but the puzzle answer is a number that makes 11 to the 110th power petty cash by comparison. What's a quantity the number of electrons in the universe would only be about the square root of? That's the magnitude of the answer.
     
  12. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    All right. I'm done.
    I shouldn't have said anything about illumination. That was a mistake. I failed to take into consideration that someone would immediately point out that the sun provides illumination. I was mentally only thinking of artificial illumination because at my work, we say either "illumination" or "sunlight" and never the two will mix.

    Anyways, yeah. The point was that it's the middle of the day. The "moon not up" was supposed to get you in an incorrect nighttime assumption.
     
  13. daniel

    daniel Cat Lovers Against the Bomb

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    I tried to figure out how to express a google or a googleplex with four toothpicks or four toothpicks and an olive pit. I suppose the pit could be a decimal point.

    A very cursory google search comes up with 10^79 as the number of electrons; so the square of that would be 10^158. Getting there with four whole toothpicks and an olive pit has me baffled. I'm generally not good at these puzzles.
     
  14. hyo silver

    hyo silver Awaaaaay

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    Four toothpicks and an olive?

    How about "1/0=", giving an answer of 'infinity'. That should be large enough. :)
     
  15. daniel

    daniel Cat Lovers Against the Bomb

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    No good. 1/0 does not equal infinity. It is undefined. IOW meaningless. When you divide 100 by 10 you are making it into ten different parts, each of which is ten. You cannot divide anything into zero parts.
     
  16. airportkid

    airportkid Will Fly For Food

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    This may give it away but the olive pit standing in for a bit of "punctuation" is not doing duty either as a decimal point or the shorthand "dot" multiplication operand.
     
  17. daniel

    daniel Cat Lovers Against the Bomb

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    Oh! It's 111! (111 factorial = about 1.76 X 10^180)
     
  18. daniel

    daniel Cat Lovers Against the Bomb

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    Actually, using 10^79 as the number of electrons, that would be the square root of 10^158. That's nowhere near the magnitude of 10^180. You'd need 10,000,000,000,000,000,000,000 10^158s to make 10^180. :eek: ;)
     
  19. airportkid

    airportkid Will Fly For Food

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    Obviously, our universe is too small. Bingo, Daniel!

    So, what is there 10^180 of? Our friend Mr. Siege Engine would say it's not quite as many questions as I keep pestering him with about his revered book, and he'd be about right, but I can't use that in the puzzle. There must be 10^180 of something though.

    Anyway, your turn, sir. Let's have the next puzzle.
     
  20. daniel

    daniel Cat Lovers Against the Bomb

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    Must there be? The physical universe is limited, though it is very large. Mathematics has no limits. You can always devise a number or mathematical concept that is larger than anyone else's just by multiplying theirs by 1.01. One might suggest that the number of possible permutations of all the particles in the universe arranged in a line is greater than 10^180, but that's not a "something," it's just another mathematical concept. I don't think there's 10^180 of anything real. Of course, 10^180 is as near zero as makes no difference if you compare it to a googolplex. And that's nothing compared to a googolplexplex (10 raised to the power of a googolplex), and I could invent a number: googolmetaplex, defined as 10 raised to the googolplex power, and that raised to the googolplex power, etc., until you have raised the result to the googolplex power a googolplex number of times. And you could top that without even raising a sweat.

    I cannot think of a logic problem. I'm not normally into logic problems. So rather than kill the thread I'll open it up to anyone who has a good one.