Question:
The volume of a sphere of radius 2r is
(a) $\frac{32 \pi r^{3}}{3}$
(b) $\frac{16 \pi r^{3}}{3}$
(c) $\frac{8 \pi r^{3}}{3}$
(d) $\frac{64 \pi r^{3}}{3}$
Solution:
(a) $\frac{32 \pi \mathrm{r}^{3}}{3}$
Volume of the sphere of radius $2 r=\frac{4}{3} \pi(2 r)^{3}=\frac{32}{3} \pi r^{3}$