2
A spherical balloon is being inflated. Its volume is increasing at a rate of $20 \, \text{cm}^3/\text{s}$. At the instant when the radius is $5 \, \text{cm}$, what is the rate of increase of its surface area? (Recall: $V = \frac{4}{3}\pi r^3$, $A = 4\pi r^2$)
Quizard
