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AQA D1 Linear programming constraint help watch

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    I'm stuck on writing a constraint for the following question 6a:

    So far I have: (assume the crocodile symbols have a _ underneath them)
    3x + 2y + z < 120
    2x + y + 3z < 100
    2x + 3y + z < 150

    I'm stuck at finding for
    'Each day, the factory must use at least twice as many components of type C as type B.'
    To me this means B > 2C
    however it states C > 2B for some reason which doesnt make sense since the statement says B needs at least twice as many of C or more, can anyone help me out please?
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    (Original post by Sayless)
    'Each day, the factory must use at least twice as many components of type C as type B.'
    To me this means B > 2C
    however it states C > 2B for some reason which doesnt make sense since the statement says B needs at least twice as many of C or more, can anyone help me out please?
    Rephrasing it one can say "the number of C's is going to be at least twice the number of B's", so C >= 2B

    At least twice as many C as B, means there's a minimum number of the C, but no max. so the constraint is going to be along the lines of " C > ",

    This type of constraint catches many people out and worth studying to ensure you understand it fully.
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    (Original post by ghostwalker)
    Rephrasing it one can say "the number of C's is going to be at least twice the number of B's", so C >= 2B

    At least twice as many C as B, means there's a minimum number of the C, but no max. so the constraint is going to be along the lines of " C > ",

    This type of constraint catches many people out and worth studying to ensure you understand it fully.
    'at least twice as many components of type C as type B'
    so this statement means at least twice as many of type B make up a type C, is the key word here 'as' which helps you depict which way round the inequality goes or is it something else?
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    (Original post by Sayless)
    'at least twice as many components of type C as type B'
    so this statement means at least twice as many of type B make up a type C, is the key word here 'as' which helps you depict which way round the inequality goes or is it something else?
    Yes, you can use the "as" as a clue.

    In general it's not sufficient though.

    If you had "at most twice as many components of type C as type B", it would be C <= 2B
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    (Original post by ghostwalker)
    Yes, you can use the "as" as a clue.

    In general it's not sufficient though.

    If you had "at most twice as many components of type C as type B", it would be C <= 2B
    Thanks a lot, gonna practise questions like that a lot to get better at spotting when I need to do this
 
 
 
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