Task: Question Answering
Input (English): Problem: kelsey travelled for 10 hours . he covered the first half of the distance at 25 kmph and remaining half of the distance at 40 kmph . find the distance travelled by kelsey ? 
Options: a ) 583 km , b ) 400 km , c ) 670 km , d ) 360 km , e ) 234 km
Output (English): b