A certain car uses 12 gallons of gasoline in traveling 120 miles. In order for the car to travel the same distance using 10 gallons of gasoline, by how many miles per gallon must the car's gas mileage be increased?
Options:
(A) 2
(B) 4
(C) 6
(D) 8
(E) 10 Think first, then make a decision. Some random thoughts:
120/10 = 12. The difference is 12- 10 = 2. So the answer is (A).