Task: Question Answering
Input (English): Problem: two cars are traveling in the same direction along the same route . the red car travels at a constant speed of 20 miles per hour , and the black car is traveling at a constant speed of 50 miles per hour . if the red car is 20 miles ahead of the black car , how many hours will it take the black car to overtake the red car ? 
Options: a ) 0.1 , b ) 0.6 , c ) 1 , d ) 1.5 , e ) 2
Output (English): b