You can set up a proportion:
1.510^3/1=1.2210^6/x
Cross multiply:
1.2210^6=1.510^3x
Solve for x:
x=(1.2210^6)/(1.510^3)
x≈813.33
Now, Divide 813.33 by 60 because the question asks for hours, not minutes:
813.33/60≈13.56
So it will take approximately 13.56 hours for them to finish filling up the swimming pool.
