A tyre has 3 punctures. The first puncture alone would have made the tyre flat in 9 minutes, the second alone would have done it in 18 minutes, the third alone would have done it in 6 minutes. If the air leaks out at a constant rate, then how long (in minutes) does it take for all the punctures together to make it flat?

A. 2

B. 6

C. 4

D. 3

Answer: Option D

Solution (By Examveda Team)

$$\therefore \frac{{18}}{{2 + 1 + 3}} = 3{\text{ minutes}}$$