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Math Help - problem solving-brain twister

  1. #1
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    Exclamation problem solving-brain twister

    hey can sumone help me with this question...becasue i forgot how to do them..and its due tomorrow for school..any help will be great!! thanks in advance

    Water from two hoses can fill a swimming pool in 4 hours. If each hose is used separately it takes 6 hours longer to fill the pool with the smaller hose than the larger hose. How long would it take to fill the pool if only the smaller hose is used.

    thanx

    PLEASE HELP
    Last edited by phatjigga; March 3rd 2007 at 04:40 PM. Reason: very very desperate
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  2. #2
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    Quote Originally Posted by phatjigga View Post
    hey can sumone help me with this question...becasue i forgot how to do them..and its due tomorrow for school..any help will be great!! thanks in advance

    Water from two hoses can fill a swimming pool in 4 hours. If each hose is used separately it takes 6 hours longer to fill the pool with the smaller hose than the larger hose. How long would it take to fill the pool if only the smaller hose is used.

    thanx

    PLEASE HELP

    Use the following law which makes this so much easier.

    Hacker's Rule of Combine Work If a man does a job in A hours and a woman does a job in B hours then the combined work is:
    AB/(A+B)


    Now, let L be the amount of time for the large tube (in this case man). Let S be the amount of time for the small tube (in this case woman). Then,
    (LS)/(L+S)=4
    We also know that,
    L+6=S

    Substitute that into the equation,
    [L(L+6)]/[L+(L+6)]=4
    Thus,
    (L^2+6L)/(2L+6)=4
    Multiply by denominator,
    L^2+6L=8L+24
    Solve quadradic for positive root.
    L=6
    That means,
    S=12.

    This is Mine 48th Post!!!
    Last edited by ThePerfectHacker; March 3rd 2007 at 05:56 PM.
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