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Number Theory stamp question

  1. Oct 30, 2013 #1
    1. The problem statement, all variables and given/known data
    There are exactly 33 postage amounts that cannot be made up using these stamps, including 46 cents. What are the values of the remaining stamps?

    2. Relevant equations
    stamp 1 = x
    stamp 2 = y
    Im assuming postage amounts range from 1 to 100 cents

    3. The attempt at a solution
    ax+by=46 has a negative solution obviously. So either a or b < 0. I cannot get any farther than that.
     
  2. jcsd
  3. Oct 30, 2013 #2

    haruspex

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    I take it there are only two stamp values.
    Can you say anything about common factors of x and y?
    Can you then determine the max value that cannot be made from them?
     
  4. Oct 30, 2013 #3

    HallsofIvy

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    I find this ambiguous. Is one of the stamps 46 cents or is one of the "postage amounts that cannot be made up" 46 cents?

    2. Relevant equations
    stamp 1 = x
    stamp 2 = y
    Im assuming postage amounts range from 1 to 100 cents

    3. The attempt at a solution
    ax+by=46 has a negative solution obviously. So either a or b < 0. I cannot get any farther than that.[/QUOTE]
     
  5. Oct 30, 2013 #4

    haruspex

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    Having solved it on the assumption that it means 46c cannot be made up, I'm pretty sure that's what is intended.
     
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