Answer:
 372 miles
Step-by-step explanation:
The appropriate relation is ...
 miles = (miles/gallon) × gallons
 distance = (31 mi/gal)×(24 gal) = 744 mi
Brittany drove 744 miles to see the ocean. Since this was her round trip distance, the one-way distance is ...
 744 mi/2 = 372 miles