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Homework Help: Basic Arithmetic Problem!

  1. Aug 5, 2007 #1
    1. The problem statement, all variables and given/known data

    LCD of 5/2x and 7/5x3y


    2. Relevant equations

    Lowest common denominator is also lowest common multiple:

    (2)(x)
    (5)(x)(3)(y) =
    (10)(x)(3)(y)

    I figured, the lowest common multiple of 2x and 5x3y is 10x3y. For some reason, my book shows the answer as 10x^2(y)!

    3. The attempt at a solution

    At this point, I don't know why I didn't come up with the same solution as the book.


    This is from the Pre-Algebra text "Preparation for Algebra" Nanney/Cable. I bought this from my college to brush up on a lot of fundamental skills I'd forgotten and this was an exercise in the beginning of the book. Is it a typo or am I just going crazy?
     
    Last edited: Aug 5, 2007
  2. jcsd
  3. Aug 5, 2007 #2

    symbolipoint

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    Do you mean
    [tex] \[
    \frac{5}{{2x}}\quad and\quad \frac{7}{{5x3y}}
    \]
    [/tex]

    If so, then LCD is [tex] \[
    2 \cdot 3 \cdot 5 \cdot xy
    \]
    [/tex]
     
  4. Aug 5, 2007 #3
    Yeah, I agree with 30xy if the denominators are 2x and 15xy each...
     
  5. Aug 6, 2007 #4

    Gokul43201

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    It's either a typo or poor quality printing.

    Does [itex]5x^2y [/itex] look a little bit like [itex]5x3y[/itex]? I'll bet the book meant the former.
     
  6. Aug 6, 2007 #5

    Yes, that's how I meant it. But I also agree with Gokul43201 in that it might be a typo or poor printing because it seems that all the other exercises in the section have a certain likeness to it... this one seemed off.

    Thanks for the help.
     
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