Task: Question Answering
Input (English): Problem: two trains, a and b, started simultaneously from opposite ends of a 120 - mile route and traveled toward each other on parallel tracks. train a, traveling at a constant rate, completed the 120 - mile trip in 6 hours; train b, traveling at a constant rate, completed the 120 - mile trip in 4 hours. how many miles had train a traveled when it met train b ?
Options: a. 28, b. 36, c. 48, d. 50, e. 54
Output (English): c