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Fundamental Math Failing

  1. Oct 31, 2011 #1
    My Fundamental Math Failing

    This should illicit a chuckle or perhaps despair in humanity.

    The statement "One silver piece is equivalent to two copper pieces" is not equivalent to the equation "S = 2C" (Where S = silver and C = copper). I cannot for the life of me figure out why. I can work out every other way that to find the number of silver pieces you take the number of copper pieces and divide by two, and therefore it becomes "S = C/2", but I cannot look at the original statement and explain precisely why that makes sense.

    I'm a physics major.
    Last edited: Oct 31, 2011
  2. jcsd
  3. Oct 31, 2011 #2


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  4. Oct 31, 2011 #3


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    Last edited: Oct 31, 2011
  5. Oct 31, 2011 #4
    That makes perfect sense, and I am still perplexed. I suppose the graph is what I have an issue with. In my mind I expect it to show equivalent exchange at all points, and it does not. It actually shows the inverse.

    This is what happens when I do not get enough sleep it seems.
    Last edited: Oct 31, 2011
  6. Oct 31, 2011 #5
    The problem is that you're using the same symbol to mean two different things. In the equation S=2C, S and C stand for the value of the silver and copper pieces. But in the equation S=C/2, S and C stand for the number of silver and copper pieces that you have (assuming that currency can be exchanged at will). Since the two equations are modeling different things, it is no surprise that the equations are different.
  7. Oct 31, 2011 #6
    Citan Uzuki, thank you very much. Order has been restored. I am quite a fool.
    Last edited: Oct 31, 2011
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