Task: Question Answering
Input (English): Problem: a woman complete a journey in 20 hours . she travels first half of the journey at the rate of 21 km / hr and second half at the rate of 24 km / hr . find the total journey in km . 
Options: a ) 334 km . , b ) 216 km . , c ) 314 km . , d ) 448 km . , e ) 544 km .
Output (English): d