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  1. #1
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    help(urgent)

    this is combined variation
    if q varies directly as b and inversely as c, and if q=0.2 when b=16 and c=8 find q when b=2 and c=5

    and

    if t varies directly as s and inversely as v-squared and if t= 0.1 when s=72 and v=6 find s when t=5 and v=0.2
    Last edited by machilove; Jan 31st 2006 at 04:47 AM.
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  2. #2
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    pls help i need it tom. I'm just new here i hope u can help me
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  3. #3
    Grand Panjandrum
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    Quote Originally Posted by machilove
    this is combined variation
    if q varies directly as b and inversely as c, and if q=0.2 when b=16 and c=8 find q when b=2 and c=5
    if $\displaystyle q$ varies directly as $\displaystyle b$ then there is a constant $\displaystyle k$ such that:

    $\displaystyle q=k\times b$

    Now when $\displaystyle q=0.2$, $\displaystyle b=16$, so:

    $\displaystyle 0.2=k \times 16$,

    so:

    $\displaystyle k=0.2/16=1/80$,

    so when $\displaystyle b=2$ we have:

    $\displaystyle q=2/80=1/40$.


    if $\displaystyle q$ varies inversely as $\displaystyle c$ then there is a constant $\displaystyle m$ such that:

    $\displaystyle q=m/c$

    Now when $\displaystyle q=0.2$ $\displaystyle c=8$, so:

    $\displaystyle 0.2=m/8$,

    so:

    $\displaystyle m=1.6$.

    Hence when $\displaystyle c=5$ $\displaystyle q=1.6/5=8/25$.

    RonL
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