Task: Question Answering
Input (English): Problem: a tyre has two punctures. the first puncture alone would have made the tyre flat in 9 minutes and the second alone would have done it in 6 minutes. if air leaks out at a constant rate, how long does it take both the punctures together to make it flat ?
Options: a. 315 min, b. 325 min, c. 335 min, d. 345 min, e. none of these
Output (English): c