Question 448309
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A milk tank can be filled by pipe A in 6 hours, by pipe B in 8 hours and by pipe C in 12 hours. 
how long will it take all three pipes working together to fill the tank?
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        Calculations in the post by @mananth are inaccurate; his solution and his answer are incorrect.

        I came to bring a correct/accurate solution in the form as it SHOULD be presented.



<pre>
First  pipe makes 1/6 of the job per hour.

Second pipe makes 1/8 of the job per hour.

Third  pipe makes 1/12 of the job per hour.


Working together, the three pipes make

    {{{1/6}}} + {{{1/8}}} + {{{1/12}}} = {{{4/24}}} + {{{3/24}}} + {{{2/24}}} = {{{(4+3+2)/24}}} = {{{9/24}}} = {{{3/8}}}

of the job per hour.


Hence, it will take  {{{8/3}}} hours,  or  2{{{2/3}}} hours, or 2 hours and 40 minutes to fill the tank,
if all three pipes work together.
</pre>

Solved.
 


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<H3>And my separate notice in the margins of my solution</H3>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I do not think that somebody will fill a milk tank during 12 hours.