Some question: A certain car uses 12 gallons of gasoline in traveling 180 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) 3
(C) 6
(D) 8
(E) 10
Some stream of consciousness:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
180/10 = 18. The difference is 18 - 15 = 3. The answer: (B).