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 72 seconds . what is the length of each train ( in meters ) ? 
Options: a ) 70 , b ) 80 , c ) 90 , d ) 100 , e ) 110
Output (English): d