The property of exponents says that when you divide two exponents with the same base, you can keep the base and subtract the exponents. So you can do 18-3, which is 15, so it would be 15 to the 15th power
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)
