2020-II-16

Ans: B
Consider the volume of the right circular cylinder, we have

$\begin{array}{rcl}
\pi \times (5a)^2 \times 7b & = & 525 \\
175\pi a^2b & = & 525 \\
\pi a^2b & = & 3
\end{array}$

Therefore, the volume of the right circular cone

$\begin{array}{cl}
= & \dfrac{1}{3} \times \pi \times (7a)^2 \times 5b \\
= & \dfrac{1}{3} \times 245 \times (\pi a^2 b) \\
= & \dfrac{1}{3} \times 245 \times 3 \\
= & 245\text{ cm}^3
\end{array}$