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Good at math but suck at puzzles

  1. Jan 6, 2012 #1
    Now i'm thinking of studying mathematics or a mathematics related subject at university, however i can't seem to let go how bad i am at puzzles/riddles. In maths tests I always get a good grade (90%+), I read around the subject etc and genuinely really enjoy it, however when i get a puzzle or a riddle which are online or in a book, i just can't do it.

    For example:

    "You need to boil eggs for exactly 9 minutes or else the visiting Duchess will
    complain, and you will lose your job as head chef.
    But you have only 2 Hourglasses, one measures 7-minutes, and the other
    measures 4-minutes. How can you correctly measure 9 minutes?"

    I couldn't figure that out, i had to look online to find the solution.

    Is riddles/puzzles like this at all related to a mathematics degree? Is there anyway i could improve on these skills, or are people just naturally good at these things.
  2. jcsd
  3. Jan 6, 2012 #2
    Performing well in puzzles doesn't really say much about an ability in mathematics. Somebody who is very good in puzzles might not be good with the abstract reasoning of mathematics.

    I wouldn't worry too much about it. If you really want to measure your ability to do mathematics, get a good math book and work through it. I like to recommend "a book of abstract algebra" by Pinter. If you enjoy the proofs and if you can work through the exercises moderately well, then you should be ok.

    Also, if you work through the Pinter book, you will be more ready to solve the riddle in question. The riddle in the OP is an example of a Diophantine equation, which are not at all easy to solve in general.
  4. Jan 6, 2012 #3
    It's just that, even easy ones i find difficult, but I'll try not to worry about it too much.

    The book you suggested, at what age is it aimed for? I'm in lower sixth form in the UK (age 16-18) which i think is senior in high school?
  5. Jan 6, 2012 #4
    Abstract algebra is a topic which is usually taught in university. But I feel that the book I suggested should be good for high-schoolers. The exercises won't always be easy though.
  6. Jan 6, 2012 #5
    May I ask what the answer to the riddle is? sorry to interupt :P
  7. Jan 6, 2012 #6
    Have you taken calculus yet? Much of the math you see in highschool isn't so much math as it is calculation/accounting. I'd take a wait and see approach- keep doing what you are doing, and take some math courses when you get to university and see if you like them.

    Run the 7 and the 4 minute together. When the 4 minute runs out, flip it over (you now have three minutes remaining in the 7).

    When the 7 minute now runs out start cooking (you now have a minute left in the 4 minute timer).

    When the four runs out, you've cooked for one minute. You can now use the 4 minute twice to time the remaining 8 minutes.
  8. Jan 6, 2012 #7
    Why not just run the 7 minute, and then run half of the 4 minute?
  9. Jan 6, 2012 #8
    How will you know that half of the 4 minutes passed?? The 9 minutes must be measured EXACTLY.
  10. Jan 7, 2012 #9
    The Answer to the Riddle:

    First thing you do is start both hourglasses.
    After the 4 minute one runs out of sand, immediately turn it over to start it again.
    After the 7 minute one runs out of sand, place the 4 minute one on its side to halt its progress. The 4 minute one should have one minute left.

    Now, since you know the 4 minute timer has one minute left, you may now cook the egg. Each time the 4 minute timer runs out you turn it over again until you get the desired amount of time. In this case since you have 1 minute left on the timer you can add 4 minutes twice for a total of 9 minutes
  11. Jan 7, 2012 #10
    Yes, we've started calculus, but nothing hard yet.
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