(d) 30 min
In one minute \(\frac{1}{27}\) part of the tank is filled. Due to leak every minute, \(\frac{1}{10}\times\frac{1}{27}\) = \(\frac{1}{270}\) part of the tank leaks out. Hence the whole tank will be emptied in 270 min by the leak.
So, resultant work by pipe and leak in one min.
= \(\frac{1}{27}\) - \(\frac{1}{270}\)= \(\frac{9}{270}\) = \(\frac{1}{30}\)
\(\therefore\) The tank will be filled in 30 min