Task: Question Answering
Input (English): Problem: a car traveled 420 miles per tankful of gasoline on the highway and 336 miles per tankful of gasoline in the city . if the car traveled 6 fewer miles per gallon in the city than on the highway , how many miles per gallon did the car travel in the city ? 
Options: a ) 14 , b ) 16 , c ) 21 , d ) 24 , e ) 27
Output (English): d