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Lv 6
? asked in Science & MathematicsMathematics · 9 years ago

algebra: work problem.. so hard.?

a tank is filled with 2 pipes. the first pipe can fill the tank in 10 hours. But after it has been opened for 3 and 1/3 hours, the second pipe is opened and the tank is filled up in 4 hours more. how long would it take the second pipe alone to fill the tank? the two pipes have different diameters.

2 Answers

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  • Ed I
    Lv 7
    9 years ago
    Favorite Answer

    The first pipe fills the tank in 1/10 hr.

    Let h = time require for second pipe to fill it.

    (1/10)(10/3 + 4) + (1/h)(4) = 1

    1/3 + 2/5 + 4/h = 1

    4/h = 1 - 1/3 - 2/5 = 4/15

    h = 15

    It would take the second pipe 15 hr to fill it.

  • 9 years ago

    so if we call a full tank "10"

    then 10 times pipe a would be 10 or 10a=10 .

    in your example the tank is, in this case, filled up to a third (three hours and 20 minutes is a third of 10 hours)

    The two thirds that are left are done in 4 hours using the second pipe, that's a third per two hours that's a whole tank in 6 hours

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