12. Three taps take 6 hours, 8 hours and 10 hours
respectively to fill a tank. All three taps were
allowed to run

By Mia

12. Three taps take 6 hours, 8 hours and 10 hours
respectively to fill a tank. All three taps were
allowed to run for 2 hours and then first and second
taps were closed. How long will it take the third
tap to fill the remaining tank?

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Mia

2 thoughts on “<br />12. Three taps take 6 hours, 8 hours and 10 hours<br />respectively to fill a tank. All three taps were<br />allowed to run”

  1. Answer:

    The remaining tank will be filled by the 3rd tap in [tex]\sf{2\dfrac{1}{2}\:hours.}[/tex]

    Given:

    • Time taken by 1st tap to fill the tank = 6 hours
    • Time taken by 2nd tap to fill the tank = 8 hours
    • Time taken by 3rd tap to fill the tank = 10 hours
    • All three taps were allowed to run for 2 hours and then first and second taps were closed.

    To Find:

    • How long will it take the 3rd tap to fill the remaining tank?

    Solution:

    Time taken by 1st tap to fill the tank = 6 hours

    Time taken by 2nd tap to fill the tank = 8 hours

    Time taken by 3rd tap to fill the tank = 10 hours

    ———————–

    Work done by 1st tap in 1 hour = 1/6

    Work done by 2nd tap in 1 hour = 1/8

    Work done by 3rd tap in 1 hour = 1/10

    ———————–

    (1st + 2nd + 3rd) tap’s 1 hour work = 1/6 + 1/8 + 1/10

    [tex]\sf{=\dfrac{20+15+10}{120}=\dfrac{45}{120}=\dfrac{3}{8}}[/tex]

    [tex]\sf{(1st + 2nd + 3rd)\: tap’s\: 2 \:hour\: work = 2\times\dfrac{3}{8} =\dfrac{3}{4}}[/tex]

    [tex]\sf{Remaining\: work =\bigg(1-\dfrac{3}{4}\bigg)=\dfrac{4-3}{4}=\dfrac{1}{4}}[/tex]

    ———————–

    Now, 1/10 work is done by 3rd tap in one hour.

    [tex]\sf{\dfrac{1}{4}\:work\:will\:be\:done \:by \:3rd\:tap\:in\bigg(\dfrac{1}{4}\div\dfrac{1}{10}\bigg)\:hours}[/tex]

    [tex]\sf{=\dfrac{1}{4}\times10=\dfrac{5}{2}=2\dfrac{1}{2}\:hours}[/tex]

    Hence, the remaining tank will be filled by the 3rd tap in [tex]\sf{2\dfrac{1}{2}\:hours.}[/tex]

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  2. Step-by-step explanation:

    Time taken by 1st tap to fill the tank = 6 hours

    Time taken by 2nd tap to fill the tank = 8 hours

    Time taken by 3rd tap to fill the tank = 10 hours

    ———————–

    Work done by 1st tap in 1 hour = 1/6

    Work done by 2nd tap in 1 hour = 1/8

    W

    ork done by 3rd tap in 1 hour = 1/10

    ———————–

    working together– 1/6+1/8+1/10

    (20+12+15/120=47/120

    working together work done- 47/120×2–47/60

    remaining work– 60-70/60–13/60

    time taken by 3rd tap to complete remaining work.

    1/10÷13/60

    6/13 hours

    reciprocal of 6/13– 13/6–

    2whole1/6

    thus third tap will take 2hrs 10mins

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