Question

Which unit rate is equivalent to 15 miles per gallon?

Answer 1

Unit rate means per 1.
This is in unit rate form already.
15 miles per 1 gallon.

If for some reason you need per 1 mile (which I've not seen written like this).
It would be 1/15th of a gallon per 1 mile

Answer 2

Answer:

incorrect

Step-by-step explanation: