Anonymous
Anonymous asked in Science & MathematicsMathematics · 5 months ago

MATH AGAIN?

One pump can empty a pool in 5 days, whereas a second pump can empty the pool in 8 days. How long will it take the two pumps, working together, to empty the pool?

The first pump's rate is

1/5

The second pump's rate is

1/8

The combined pumps rate is

13/40

It will take the two pumps

days to empty the pool together. =

10 Answers

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  • 5 months ago

    3.077 days

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  • geezer
    Lv 7
    5 months ago

    If the combined pumps rate is 13/40 ..

    the time will be 40/13 days ..

    3 1/13 days ..

    3 days and almost 2 hours (1/12 would be exactly 2 hours)

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  • sepia
    Lv 7
    5 months ago

    One pump can empty a pool in 5 days, whereas a second pump can empty the pool in 8 days.

    How long will it take the two pumps, working together, to empty the pool?

    The first pump's rate is 1/5. The second pump's rate is 1/8.

    The combined pumps rate is 13/40

    It will take the two pumps 3.07..days to empty the pool together.

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  • nbsale
    Lv 6
    5 months ago

    Pay attention to the units. What are the units in a rate of "1/5"? It's one pool per 5 days.

    So when you add the rates (the proper thing to do), you get 13/40, meaning 13 pools in 40 days, or since 13/40 = 1/(40/13), it's one pool per 40/13 days = 3 1/13 days = 3.076923... days (last 6 digits repeat).

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  • 5 months ago

    The first pump could empty the pool 8 times in 40 days, and the second pump could empty the pool 5 times in 40 days.

    Together they could empty the pool 13 times in 40 days, so (dividing through by 13) it will take the two pumps 40/13

    days to empty the pool together.

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  • 5 months ago

    "One pump can empty a pool in 5 days, whereas a second pump can empty the pool in 8 days."

    "How long will it take the two pumps, working together, to empty the pool?"

    (5*8) / (5+8) = 40/13 days (about 3 and 1/13 day)

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  • Mike G
    Lv 7
    5 months ago

    t/5+t/8 = 1

    t = 40/13 days

    = 3.077 days

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  • Anonymous
    5 months ago

    In one day the first pump can empty 1/5 of the pool.

    In one day, the second pump can empty 1/8 of the pool.

    In one day, both pumps can empty 1/5 + 1/8 = 13/40 of the pool.

    time = 1 / (13/40) = 40/13 days. A little over 3 days.

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  • 5 months ago

    where is the answer? how many days to empty the pool?

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  • Bryce
    Lv 7
    5 months ago

    1/5 + 1/8= 1/T

    T= 40/13 days

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