Question 34941
Hello!

You might want to see my <a href=http://www.algebra.com/tutors/HOW_TO_Solve_Rate_of_Work_Problems.lesson?content_action=show_dev>lesson</a> on this subject.

Let's call X to the number of hours it takes for the smaller pipe to fill the tank when working alone. Applying the formula mentioned in the lesson, you get:

{{{1/9 + 1/X = 1/6}}}

So now we just solve for X:

{{{1/X = 1/6 - 1/9 = 1/18}}}
{{{X = 18}}}

So the small pipe takes 18 hours to fill the pool.


I hope this helps!
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