Task: Question Answering
Input (English): Problem: at 1 : 00 pm , a truck left city p and headed toward city q at a constant speed of 50 km / h . one hour later , a car left city q and headed toward city p along the same road at a constant speed of 40 km / h . if the distance between city p and city q is 230 km , at what time will the truck and the car meet each other ? 
Options: a ) 4 : 00 , b ) 4 : 30 , c ) 5 : 00 , d ) 5 : 30 , e ) 6 : 00
Output (English): a