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    thought I'd be able to use substitution but struggling.
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    What is this? Algebra? There must be more to the question.
    You've got 1 equation and 2 variables so there's an infinite number of answers.
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    (Original post by Trackstar)
    thought I'd be able to use substitution but struggling.
    need more info
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    (Original post by Trackstar)
    thought I'd be able to use substitution but struggling.
    Do you mean

    30 = 24 r + 42 s where r and s are whole numbers?

    If so, for numbers this size, trial and error is probably the quickest solution, although you might as well divide through by 6 so you're solving

    5 = 4 r + 7 s.

    It's also worth noting that if you find a solution to

    1 = 4 r + 7 s,

    you can just multiply r and s by 5 to get a solution to 5 = 4r + 7s.

    Edit: for a non-trial-and-error method, you could look up the Extended Euclidean Algorithm, but I feel this will probably be overkill...
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    (Original post by DFranklin)
    Do you mean

    30 = 24 r + 42 s where r and s are whole numbers?

    If so, for numbers this size, trial and error is probably the quickest solution, although you might as well divide through by 6 so you're solving

    5 = 4 r + 7 s.

    It's also worth noting that if you find a solution to

    1 = 4 r + 7 s,

    you can just multiply r and s by 5 to get a solution to 5 = 4r + 7s.

    Edit: for a non-trial-and-error method, you could look up the Extended Euclidean Algorithm, but I feel this will probably be overkill...
    no, this just confirmed my method was wrong. the question is. b=24, c=42 find r,s such that q=rb+sc for,

    q=30
    q=32
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    (Original post by Trackstar)
    no, this just confirmed my method was wrong. the question is. b=24, c=42 find r,s such that q=rb+sc for,

    q=30
    q=32
    You still have 2 variables and only 1 equation. Doesn't it say anything else about r and s?
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    Can u show us the full question?
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    (Original post by Trackstar)
    no, this just confirmed my method was wrong. the question is. b=24, c=42 find r,s such that q=rb+sc for,

    q=30
    q=32
    You really need to clarify whether r and s are supposed to be integers. The form of question strongly indicates that they are, however:

    Spoiler:
    Show
    It's not possible to find integer r,s s.t. 24 r + 42 s = 32.
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    (Original post by DFranklin)
    You really need to clarify whether r and s are supposed to be integers. The form of question strongly indicates that they are, however:

    Spoiler:
    Show

    It's not possible to find integer r,s s.t. 24 r + 42 s = 32.
    they are sorry, I have done it now.
 
 
 
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