Task: Question Answering
Input (English): Problem: when a train travels at a speed of 70 kmph , it reaches the destination on time . when the same train travels at a speed of 50 kmph , it reaches its destination 15 min late . what is the length of journey ? 
Options: a ) 37.5 km , b ) 50.5 km , c ) 60 km , d ) 85.5 km , e ) 95 km
Output (English): a