OE


Let the radius of the cistern be ' $r$ ' meter.

If the water rises 0.1 meter in one second, it would rise $\(0.1 \times 60=6\)$ meter in one minute.

We know that water runs in the cylindrical cistern at the rate of $\(924 \mathrm{~m}^3\)$ per minute, so we get the volume of the cylindrical cistern as $\(\pi r^2 h=924 \mathrm{~m}^3\)$ i.e.

$\(\frac{22}{7} \times r^2 \times 6=924\)\( \Rightarrow r=\sqrt{924 \times \frac{7}{22} \times \frac{1}{6}\)\(=7\)$ meter

Hence the answer is (B).