9 gals/second
xgals/minute
1 minute=60 seconds
xgals/60 seconds=9gals/1 second
x/60=9/1
solve for x
x/60=9/1
x/60=9
multily both sides by 60 to clear fraciton
x times 60/60=9 times 60
x times 60/60=x times 1=x
x=540
the answer is 540 gallons per minute