Task: Question Answering
Input (English): Problem: two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 22 seconds. the ratio of their speeds is ?
Options: a. 3 / 1, b. 3 / 1, c. 1 / 1, d. 3 / 5, e. 5 / 2
Output (English): c