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Let x be the time for the large pipe to fill the tank working alone, in minutes.
Then the time for the small pipe to fill the tank working alone is (t+8) minutes.
The larger pipe fills of the tank volume per minute.
The smaller pipe fills of the tank volume per minute.
The two pipes fill of the tank volume, working simultaneously.
The condition says
= 1.
---> 3*(x+8) + 3x = x*(x+8) ---> = ---> (x-6)*(x+4) = 0 ---->
the only positive root is t= 6 minutes.
Answer. 6 minutes for the large pipe to fill the tank, and 6 + 8 = 14 minutes for the small pipe.
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For a wide variety of similar solved joint-work problems with detailed explanations see the lessons
- Using Fractions to solve word problems on joint work
- Solving more complicated word problems on joint work
- Selected joint-work word problems from the archive
in this site.
Read them and get be trained in solving joint-work problems.
Also, you have this free of charge online textbook in ALGEBRA-I in this site
- ALGEBRA-I - YOUR ONLINE TEXTBOOK.
The referred lessons are the part of this textbook under the topic "Rate of work and joint work problems" of the section "Word problems".