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