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Complex Engineering Puzzle

  1. Apr 26, 2009 #1
    Complex Engineering Puzzle!!!

    Distribute 20 lbs of pressure in 5 hours, the numbers Must be Odds and each hour must have a value; you cant use even numbers, nor frations, just positives completes!!

    wich are the values??
  2. jcsd
  3. Apr 26, 2009 #2


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    Gold Member

    Re: Complex Engineering Puzzle!!!

    I'm sorry, dude, but that question doesn't really make any sense as presented. Can you express it a bit more accurately?
  4. Apr 26, 2009 #3
    Re: Complex Engineering Puzzle!!!

    errr wouldnt one of the numbers have to be zero for this to work?? otherwise you would always get at least one even number... right?
  5. Apr 27, 2009 #4
    Re: Complex Engineering Puzzle!!!

    There is not one single answer, but here is one possible answer:
    midnight - 1
    1 0'clock - 1
    2 0'clock - 1
    3 0'clock - 1
    4 0'clock - 1
    5 0'clock - 15
    That's an odd number at each hour, and 20 in 5 hours.
    NBAJam100, zero is an even number.
  6. Apr 27, 2009 #5
    Re: Complex Engineering Puzzle!!!


    your solution takes 6 hours (rounding up). There is no solution to this question for 5 hours.
  7. Apr 27, 2009 #6
    Re: Complex Engineering Puzzle!!!

    You could wait until daylight savings to switch, then 5 hours magically becomes 4 or 6, and you're golden.

    Technically, Jimmy's takes 5 hours, not 6 hours, it's just that it doesn't take up a full hour. So he's assuming (for example):

    12:30:00 - 1
    1:30:00 - 1
    2:30:00 - 1
    3:30:00 - 1
    4:30:00 - 1
    5:29:59 - 15

    Hence, the "hour" of midnight has 1 in it, and the "hour" of 1 has 1 in it, etc. At least, that's my understanding of his answer.

    Last edited: Apr 27, 2009
  8. Apr 27, 2009 #7
    Re: Complex Engineering Puzzle!!!

    Round down.
  9. Apr 27, 2009 #8
    Re: Complex Engineering Puzzle!!!

    Your solution takes 4 hours, 59 minutes and 59 seconds. Mine takes 5 hours.
  10. Apr 27, 2009 #9
    Re: Complex Engineering Puzzle!!!

    That gets into the discussion of whether or not you can measure an infinitesemal unit of time, of course-- I was just going by the "normal" measure of time which is to say that since the majority of the full second at 5:30:00 lies AFTER the 5 hour mark, you usually measure the hour to the tail end of the preceeding second. Sort of like why 12:00:00 is PM instead of AM or just "M". The time between the instant it hits 12:00:00 and the instant it hits 12:00:01 is for all intents and purposes 100% (immeasurably smaller) in PM rather than "M", and hence is considered "PM".

    But that's just semantics.

  11. Apr 27, 2009 #10
    Re: Complex Engineering Puzzle!!!

    The problem specifies that you must do it in 5 hours. Your solution is over the range of [0,5] which takes more than 5 hours, and is therefore an invalid solution. You need a solution that is in the range (0,5) or (0,5] or [0,5).
  12. Apr 27, 2009 #11
    Re: Complex Engineering Puzzle!!!

    It's not actually taking more than 5 hours-- it's taking *exactly* 5 hours (rounding up or down will yield the same result), and is assuming something that's physically impossible, but mathematically correct. If you imagine a square aligned in the XY plane, for instance, with 1 corner at the origin, and side lengths of 5, the corner on the Y axis isn't at 0,4.9999...., it's at 0,5. So he's basically assuming you can distribute it instantaneously.

  13. Apr 27, 2009 #12
    Re: Complex Engineering Puzzle!!!

    good point... hahaha
  14. Apr 27, 2009 #13
    Re: Complex Engineering Puzzle!!!

    The length of (0,5), (0,5], [0,5) and [0,5] were all 5 when I went to school.
  15. Apr 28, 2009 #14


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    Re: Complex Engineering Puzzle!!!

    There must be a value each hour. But maybe a value anytime. So, it´s easy...
  16. Apr 4, 2011 #15
    Re: Complex Engineering Puzzle!!!

    The riddle is impossible, junglebeast is correct.
    The riddle states that every hour must have a value,
    This doesnt mean each period of time ending in 00 has a value.

    That means every 60 minute interval must have a value.
    there are only 5 hours in 5 hours (obviously) thus you must have 5 numbers.
    Jimmys solution is providing 6. Thus invalid

    The reason it is impossible is, if you must chose 5 numbers that add up to 20 it is impossible without chosing an even number.
    Any odd number times an odd number creates an even number, always.
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