Question

plz answer me guys

Best answer will be mark as brainliest

Answer 1

13.

∵ A pipe can fill a cistern in 6 hrs.

∴ The part of cistern filled by this pipe in an hour = 1/6 th part

∵ Due to a leak in the bottom  it is filled in 7 hrs.

∴  ''       ''         ''     the part of cistern filled in an hour = 1/7 th part .

Now,

This leak can empty the part of cistern in an hour = (1/6 - 1/7) th part

                                                                                       = 1/42  th part.

The total time taken by this leak to empty = 42 hrs.

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14.  

       There are two inlets A and B and  an outlet .

   ∵ A can fill it in 15 hrs.

    ∴  Part of cistern filled by A in an hour = 1/15 th part.

 

∵ B can fill it  in 20 hrs.

∴ Part of cistern filled by B in an hour = 1/20 th part.

∵ An outlet can empty in 12 hrs.

∴ Part of cistern emptied by an outlet in an hour = 1/12 th part.

• If all three pipes are opened together.

Then

  The part of cistern will fill  in  an hour = (1/15 + 1/20 ) - 1/12

                                                                    = 7/60 - 1/12 = 2/60 = 1/30 th

So

It will be filled in 30 hrs.

Thank u.

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