Task: Question Answering
Input (English): Problem: on a trip covering 850 km , a bicyclist travels the first 400 km at 20 km per hour and the remainder of the distance at 15 km per hour . what is the average speed , in km per hour , for the entire trip ? 
Options: a ) 16.0 , b ) 16.5 , c ) 17.0 , d ) 17.5 , e ) 18.0
Output (English): c