If the volume and the surface area of a sphere are numerically the same, the nits radius is
Question:

If the volume and the surface area of a sphere are numerically the same, the nits radius is
(a) 1 unit
(b) 2 units
(c) 3 units
(d) 4 units

Solution:

(c) 3 units

We have:

$\frac{4}{3} \pi r^{3}=4 \pi r^{2}$

$\Rightarrow \frac{1}{3} r=1$

$\Rightarrow r=3$ units