Task: Question Answering
Input (English): Problem: when sourav increases his speed from 20 km / hr to 25 km / hr , he takes one hour less than the usual time to cover a certain distance . what is the distance usually covered by him ? 
Options: a ) 125 km , b ) 100 km , c ) 80 km , d ) 120 km , e ) 60 km
Output (English): b