Calculus problem

Question

A spherical balloon is inflated with gas at the rate of 800 cubic centimeters per minute. Find the rate of change of the radius when 𝑟 = 30 centimeters. (The volume of a sphere is found using 𝑉 = 4/3 𝜋𝑟³ ).

Answer 1

V = (4/3)πr³

dV/dt = 4πr²(dr/dt)

800 = 4π(30)²(dr/dt)

dr/dt = 2/(9π) cm/min