Task: Question Answering
Input (English): Problem: two trains of equal length are running on parallel lines in the same direction at 46 km / hr and 36 km / hr . the faster train catches and completely passes the slower train in 18 seconds . what is the length of each train ( in meters ) ? 
Options: a ) 20 , b ) 25 , c ) 35 , d ) 50 , e ) 65
Output (English): b