Here's what you need to know in order to answer this:
1 gallon = 128 fl oz
and
1 day = 24 hours.
Use those facts to invent fractions equal to ' 1 '.
Then use those to change the units of the "11 fl oz per hour".
You can multiply them ... since their value is ' 1 ', they won't
change the value of the "11 fl oz per hour", only the units.
(11 fl oz/hr) x (24 hr/da) x (1 gal / 128 fl oz)
= (11 x 24 x 1 / 128) (fl-oz - hr - gal) / (hr - da - fl-oz)
= 2.0625 gal/da
