<PRE><B>Question 1161576</B>
.
&lt;pre&gt;

Pump A makes  {{{1/5}}}  of the job per hour;

Pump B makes  {{{1/8}}}  of the job per hour;

Pump C makes  {{{1/10}}}  of the job per hour.


Working together, the three pumps make  {{{1/5 + 1/8 + 1/10}}} = {{{8/40 + 5/40 + 4/40}}} = {{{17/40}}}  of the job per hour.


Hence, it will take  {{{40/17}}} hours = 2{{{6/17}}} hours = 2 hours and 21 minutes (approximately)  for the three pumps to empty the tank,
working tofether.
&lt;/pre&gt;

Solved.


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It is a standard and typical joint work problem.


There is a wide variety of similar solved joint-work problems with detailed explanations in this site. &amp;nbsp;See introductory lessons

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;- &lt;A HREF=http://www.algebra.com/algebra/homework/Rate-of-work-word-problems/Word-problems-WORKING-TOGETHER-by-Fractions.lesson&gt;Using Fractions to solve word problems on joint work&lt;/A&gt; 

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;- &lt;A HREF=http://www.algebra.com/algebra/homework/Rate-of-work-word-problems/Solving-more-complicated-word-problems-on-joint-work.lesson&gt;Solving more complicated word problems on joint work&lt;/A&gt; 

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;- &lt;A HREF=https://www.algebra.com/algebra/homework/Rate-of-work-word-problems/Selected-problems-from-the-archive-on-joint-work-word-problems.lesson&gt;Selected joint-work word problems from the archive&lt;/A&gt; 

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;- &lt;A HREF=https://www.algebra.com/algebra/homework/Rate-of-work-word-problems/Joint-work-word-problems-for-3-4-5-participants.lesson&gt;Joint-work problems for 3 participants&lt;/A&gt;


Read them and get be trained in solving joint-work problems.


Also, &amp;nbsp;you have this free of charge online textbook in ALGEBRA-I in this site

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;- &lt;A HREF=https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson&gt;ALGEBRA-I - YOUR ONLINE TEXTBOOK&lt;/A&gt;.


The referred lessons are the part of this textbook under the topic 
&quot;&lt;U&gt;Rate of work and joint work problems&lt;/U&gt;&quot; &amp;nbsp;of the section &amp;nbsp;&quot;&lt;U&gt;Word problems&lt;/U&gt;&quot;.



Save the link to this online textbook together with its description


Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson


to your archive and use it when it is needed.


</PRE>