Task: Question Answering
Input (English): Problem: a walks at 4 kmph and 4 hours after his start , b cycles after him at 10 kmph . how far from the start does b catch up with a ? 
Options: a ) 62.6 km , b ) 26.7 km , c ) 22.8 km , d ) 19.5 km , e ) none
Output (English): b