a. We have to find how many miles each car can travel with 1 gallon of gas.
For the blue car, we can use the next proportion:

Solving for x:

Blue car's mileage: 28.4 miles per gallon
b. For the silver car, we can use the next proportion:

Solving for x:

Silver car's mileage: 34 miles per gallon
c. Silver car