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Homework Help: Algebra. 2

  1. Apr 13, 2004 #1
    If x and y are whole numbers that don't have10 as a factor, and if xy = 1,000, find x + y.
     
  2. jcsd
  3. Apr 13, 2004 #2

    turin

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    Homework Helper

    Make a list of prime factors of 1000. Distribute this into two sub-lists. Make sure that neither sub-list contains a 2 and 5 in the same sub-list. Hint, there are 6 prime factors, only two distinct, and only one way to divy them up according to these rules.
     
  4. Apr 13, 2004 #3
    The list

    I need more help.!!!
     
  5. Apr 14, 2004 #4
    This is what turin means

    1000 = 5*5*5*2*2*2

    To distribute this into sublists looks like this:

    Code (Text):
    2         2*2*5*5*5
    2*2      2*5*5*5
    But we can't have both 2 and 5 in either sublists (that would give us a multiple of 10).

    So the only way to resolve this is to have all the two's in one sublist and the three 5's in the other sublists, so we have: 2*2*2= 8 and 5*5*5 = 125.

    x = 8, y=125
     
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