Given:
Marco drains his pool water at a rate of 12 gallons per minute.
To convert gallons per minute to gallons per second:
We know that, one minute= 60 seconds.
So,
[tex]\begin{gathered} 12\text{ gallons per minute}=\frac{12}{60}\text{gallons per second} \\ =0.2\text{ gallons per second} \end{gathered}[/tex]Hence, the answer is 0.2 gallos per second.