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Need Help With an Equation

Discussion in 'After Hours Lounge (Off Topic)' started by WillG, Jun 17, 2007.

  1. WillG

    WillG Well-Known Member

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    This may seem like simple stuff for some of you geniuses here (sincerely) but I have not done this in years. My wife is studying for a financial test with math she has not done in years. And this has got me somewhat stumped as well.

    Can someone show me how to solve for x in the following equation

    362.81=350.45+350.45(.0525)-350.45x

    x=1.7231

    Thanks in advance
     
  2. SethH

    SethH Well-Known Member

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    1. Mulitiply 350.45*0.0525 (=18.398625)
    2. Add the result above to 350.45 (=368.848625)
    3. Move result to left side of equation by subtracting it over (=-6.038625)
    4. Divide result above by -350.45

    X = 0.017231 . . .
     
  3. Keith Mickunas

    Keith Mickunas Well-Known Member

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    This is an odd looking formula, but it's not hard to solve at all. First subtract the two numbers on the right that don't have X from both sides. Then merely divide by -350.45.
     
  4. WillG

    WillG Well-Known Member

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    Oh, so I guess that makes me dumb [​IMG]

    Just kidding

    I figured out what I was doing wrong. I was trying to solve it in Excel. And I typed in, literally (.0525) which Excel treated as a negative number I've had a few beers

    Thanks. I can use the refresher
     
  5. BrianW

    BrianW Well-Known Member

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    Another way to look at it is to associate everything on the right side of the equation, which is made possible by every term on the right side having the explicit factor of 350.45 (presumably the beginning balance of an interest-bearing account, or something like that):


    362.81 = 350.45 + 350.45(.0525) - 350.45x

    362.81 = 350.45(1 + .0525 - x)

    362.81 / 350.45 = 1.0525 - x

    x = 1.0525 - (362.81 / 350.45)

    x = 0.017231


    It yields exactly the same answer (and is algebraically equivalent to) the responses above, but I find that thinking of it in this way is helpful because it associates the beginning balance factor (1) with the interest earned (.0525) and the interest deducted (x) together to give you a single number (1 + .0525 + x) to multiply by the beginning balance (350.45) to arrive at the ending balance (362.81). This gives me a simple formula that relates beginning balance with ending balance, which is much easier for me to wrap my brain around.

    [Edit: Sorry, Will, you slipped your last one in before I could finish my response. Had I known that beer was involved, I would have tailored my answer accordingly. [​IMG]]
     
  6. Joseph DeMartino

    Joseph DeMartino Well-Known Member

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  7. Keith Mickunas

    Keith Mickunas Well-Known Member

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    I knew Excel could be set to display numbers in parenthesis when they are negative, but I didn't think it'd interpret them that way, that's not intuitive at all to me, but then I was a math major, I don't do business math much.
     
  8. Joseph DeMartino

    Joseph DeMartino Well-Known Member

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    Wait a minnit - this is the HTF and we don't have a beer smiley, like the one seen here?

    Regards,

    Joe
     
  9. BrianW

    BrianW Well-Known Member

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    :lager:

    :ale:

    :malt liquor:

    :lite beer:

    :near beer:

    :beerbeerBEER:



    Sorry, Joe. Can't help you.
     
  10. andrew markworthy

    andrew markworthy Well-Known Member

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    :vintage claret:

    That doesn't work either.
     
  11. BrianW

    BrianW Well-Known Member

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    Ooooh! Now we're getting fancy!



    [​IMG]
     

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