At a speed of 40 miles per hour, a certain car uses 1 gallon of gasoline every 40 miles. If the car starts with a full 12 gallon tank of gasoline and travels for 5 hours at 40 miles per hour, the amount of gasoline used would be what fraction of a full tank?
Choose the correct answer.
A) 3 / 25  B) 5 / 12  C) 7 / 12  D) 2 / 3  E) 25 / 36

Rationale: "gas used = ( 5 hours ) * ( 40 miles / hour ) * ( 1 gallon / 40 miles ) = 5 gallons portion used = ( 5 ) / 12 = 5 / 12 ans b"
Answer: B