A tyre has two punctures. The first puncture along 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?	Pick:
A) 1 1⁄2 minutes  B) 3 1⁄2 minutes  C) 3 3⁄5 minutes  D) 4 1⁄4 minutes  E) None of these
1 minute’s work of both the punctures = (1⁄9 + 1⁄6) = 5⁄18   So, both the punctures will make the tyre flat in 18⁄5 = 33⁄5 min.   Answer 3 3⁄5 minutes
<result>C</result>
A tyre has two punctures. The first puncture along 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?