suppose that the gas tank of a car holds 12 gallons and that the car uses 1/ 20 of a gallon per mile .let x be the nuber of miles the car has gone since the tank was filled?

(1/20x)= 12
so now get x by itslef!
(1/20x)/ (1/20)= 12/(1/20)
x= 240!
yeah I am good! that is good! good luck!

Liz gave you the total miles per tank.
x=20(gallons used) If your tank is half full, you have used 6 gallons,so
x=20(6)
x=120
if your tank is 3/4 full you have used 3 gallons, so
x=20(3)
x=60