Answer: the correct answer is 11 hours, 21 seconds and 3738 fractions of a second.
Step-by-step explanation:
An American gallon has 3.78541 liters.
3,600 gallons are 13,627.46 liters since 3,600 gallons * 3.78541 liters per gallon= 13,627.46 liters
We will need 681.3738 minutes to fill the pool since 13,627.46 liters divided by 20 liters per minute = 681.3738 minutes
681.3738 minutes is 11 hours and 21.3738 seconds since 11*60 minutes + 21.3738 minutes = 660 minutes + 21.3738 seconds = 681.3738 or 681.3738 divided by 60 minutes ( 1 hour ) is 11 hours and 21.3738 seconds.
