The Fuel efficiency rate in miles per gallon is; 104.67 MPG
Let the initial amount of gallons be x
Now, after driving for 263 miles, you have 11 gallons of gas left in your tank.
Now, you continue driving and after driving 314 miles, you have 8 gallons left. This means that number of gallons used to drive 314 miles = 11 - 8 = 3 gallons
Therefore the Fuel efficiency rate which is in miles per gallon is;
MPG = 314/3
MPG = 104.67 MPG
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