A large pipe can fill a tank in 6 hours less than it takes the small pipe. Working together, they can fill it in #4# hours. How long would it take the small pipe to fill the tank if it was working alone?
Let the time it takes to fill the smaller pipe be
Then, the amount of tank that can be filled in
Solve this equation.
We can now eliminate the denominators.
Two solutions may seem non sensical, but if you determine the length of time it takes using the large pipe, you will get
So, it takes the small pipe
Hopefully this helps!