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  3. Math problem -- help/hints please (NOW SOLVED: includes solution)

Math problem -- help/hints please (NOW SOLVED: includes solution)

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  • K Kevin Bewley

    Bang on (although the 'book answer' is 7/10 - simplest fractional answer). I'm curious about your notation though, what's with the factorial -1?

    C Offline
    C Offline
    cpkilekofp
    wrote on last edited by
    #23

    LOL, cool, that's the answer I got. Those mangled signs will get you every time.

    "Seize the day" - Horace "It's not what he doesn't know that scares me; it's what he knows for sure that just ain't so!" - Will Rogers, said by him about Herbert Hoover

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    • J J4amieC

      I can tell you the answer is 7/10 but not because I can remember how to solve this from A-Level maths, but because I long ago realised such things are futile, and excel can solve this much quicker than I can.

      D Offline
      D Offline
      dan sh
      wrote on last edited by
      #24

      J4amieC wrote:

      excel can solve this much quicker than I can

      Have become a manager?

      "Fear no factor", Prime Numbers.

      J 1 Reply Last reply
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      • K Kevin Bewley

        Okay, so I've dug out my old A-level maths text to try and brush up on my skills. I've managed to struggle through the 1st chapter and associated exercises but have one question that I've got wrong and I can't for the life of me figure out where I'm going wrong. So, if any of you guys can help point me in the right direction I'd be really grateful: So I have the following I need to solve for x: (x-4)/6 - 2x+1 = (3x-4)/2 My approach was to find the lcm, which is 6 and then do this: 1(x-4) - 6(2x+1) = 3(3x-4) multiply out the brackets: x-4 - 12x-6 = 9x-12 which yields: 20x = 2 or x = 1/10 However, the back of the book says I'm wrong. It's really bugging me - I feel I'm falling at first step as I'm pretty confident once I've removed the fractional component that I'm doing everything correctly. Thanks guys, Kev Correct Solution follows: (x-4)/6 - 2x+1 = (3x-4)/2 lcm is 6 so multiply out the terms: 1(x-4) + 6(-2x+1) = 3(3x-4)/2 => This is where I'd gone wrong 6(-2x+1) multiplying out: x -4 -12x +6 = 9x -12 -4 +6 +12 = 9x -x +12x 14=20x x=14/20 or 7/10 YAY!

        S Offline
        S Offline
        Sumal V
        wrote on last edited by
        #25

        Well I hope you've found the right answer Kevin..

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        • S Sumal V

          Well I hope you've found the right answer Kevin..

          K Offline
          K Offline
          Kevin Bewley
          wrote on last edited by
          #26

          Yes I have - and I learned something about CHECKING the bloody signs!! :-D Thanks guys - I can now confidently move onto the next chapter knowing I'm not missing something critical! This is the first time I've used CodeProject this way and I'm well impressed by the generosity of you guys.. :thumbsup:

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          • D dan sh

            J4amieC wrote:

            excel can solve this much quicker than I can

            Have become a manager?

            "Fear no factor", Prime Numbers.

            J Offline
            J Offline
            J4amieC
            wrote on last edited by
            #27

            d@nish wrote:

            Have become a manager?

            If I had turned into a manager I would be using Project to organise people to document the problem, an architect to design the proper implementation to solve the solution, developers to develop the solution and testers to provide automated testing that the solution fulfils the requirements. A smart person like me just plugged the 2 sides of the equation into a goalseak in Excel and came out with a solution in about 30 seconds.

            D 1 Reply Last reply
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            • J J4amieC

              d@nish wrote:

              Have become a manager?

              If I had turned into a manager I would be using Project to organise people to document the problem, an architect to design the proper implementation to solve the solution, developers to develop the solution and testers to provide automated testing that the solution fulfils the requirements. A smart person like me just plugged the 2 sides of the equation into a goalseak in Excel and came out with a solution in about 30 seconds.

              D Offline
              D Offline
              dan sh
              wrote on last edited by
              #28

              I see how cleverly you have omitted all the rant causing things done by managers in your post. :)

              "Fear no factor", Prime Numbers.

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              • K Kevin Bewley

                Okay, so I've dug out my old A-level maths text to try and brush up on my skills. I've managed to struggle through the 1st chapter and associated exercises but have one question that I've got wrong and I can't for the life of me figure out where I'm going wrong. So, if any of you guys can help point me in the right direction I'd be really grateful: So I have the following I need to solve for x: (x-4)/6 - 2x+1 = (3x-4)/2 My approach was to find the lcm, which is 6 and then do this: 1(x-4) - 6(2x+1) = 3(3x-4) multiply out the brackets: x-4 - 12x-6 = 9x-12 which yields: 20x = 2 or x = 1/10 However, the back of the book says I'm wrong. It's really bugging me - I feel I'm falling at first step as I'm pretty confident once I've removed the fractional component that I'm doing everything correctly. Thanks guys, Kev Correct Solution follows: (x-4)/6 - 2x+1 = (3x-4)/2 lcm is 6 so multiply out the terms: 1(x-4) + 6(-2x+1) = 3(3x-4)/2 => This is where I'd gone wrong 6(-2x+1) multiplying out: x -4 -12x +6 = 9x -12 -4 +6 +12 = 9x -x +12x 14=20x x=14/20 or 7/10 YAY!

                A Offline
                A Offline
                Arul R Ece
                wrote on last edited by
                #29

                x=7/10

                S 2 Replies Last reply
                0
                • A Arul R Ece

                  x=7/10

                  S Offline
                  S Offline
                  Sumal V
                  wrote on last edited by
                  #30

                  Hey, the problem is solved already ;)

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                  • K Kevin Bewley

                    Of course!! Thanks buddy! :-)

                    M Offline
                    M Offline
                    Manfred Rudolf Bihy
                    wrote on last edited by
                    #31

                    You're welcome! :-D

                    "With sufficient thrust, pigs fly just fine."

                    Ross Callon, The Twelve Networking Truths, RFC1925

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                    • A Arul R Ece

                      x=7/10

                      S Offline
                      S Offline
                      Sumal V
                      wrote on last edited by
                      #32

                      If someone is down-voting, please give reasons

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