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Applications of Linear Equations Monetary Word Problem

  1. Apr 30, 2005 #1
    This is the problem:
    Lorraine has $7.70 in dimes and quarters. If the number of quarters is two more than twice the number of dimes, how many of each type does she have?
    I know the answer is 12 dimes and 26 quarters by figuring it in my head, but my professor requires us to show work to get credit of course and I can't come up with a working formula.
    What I have so far figured is this:
    25x + 20x + 20 + 10x - 10x = 770
    45x = 750
    x = 16.666... To me this won't work and I've been working on it for quite a while and can't really figure out what I'm doing wrong. I am using a formula that the professor went over in class, but like many other times, the problems we go over in class aren't quite like what we have for homework. I would appreciate any help anyone could offer.
    Last edited: Apr 30, 2005
  2. jcsd
  3. Apr 30, 2005 #2
    Let y be the number of dimes and x be the number of quarters. Then

    [tex]25x + 10y = 770[/tex]



    Now just solve~
  4. Apr 30, 2005 #3

    Thanks a bunch, I don't know why I couldn't figure that out, I really appreciate your help.
    -dajohu :smile:
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