Question

One inlet pipe can fill an empty pool in 6 hours, and a drain can empty the pool in 8 hours. How long will it take the pipe to fill the pool if the drain is left open? hours

Answer 1

Okay, here we have this:

1/6 = portion of pool filled per hour by the inlet pipe

1/8 = portion of pool emptied per hour by the drain

So, we are going to consider portion of pool filled per hour if the inlet pipe and drain are both open as 1/x.

Therefore we obtain the following equation:

`(1)/(6)-(1)/(8)=(1)/(x)`

Now, we need clear x:

`\begin{gathered} x((1)/(6)-(1)/(8))=1 \\ x((1)/(24))=1 \\ (x)/(24)=1 \\ x=24 \end{gathered}`

Finally we obtain that