If the rate of change of volume of a sphere is the same as rate of change of its radius, then radius is equal to:
Answer & explanation
Correct answer: option 2
$V=\frac{4}{3}πr^3;\frac{dV}{dt}=\frac{4}{3}π×3r^2\frac{dr}{dt}=\frac{dr}{dt}⇒r=\frac{1}{2\sqrt{π}}$