Task: Question Answering
Input (English): Problem: the pilot of a small aircraft with a 40 - gallon fuel tank wants to fly to cleveland , which is 480 miles away . the pilot recognizes that the current engine , which can fly only 6 miles per gallon , will not get him there . by how many miles per gallon must the aircraft ’ s fuel efficiency be improved to make the flight to cleveland possible ? 
Options: a ) 2 , b ) 4 , c ) 12 , d ) 6 , e ) 160
Output (English): d