Question

Air is being pumped into a spherical hot air balloon at a rate of 50 cm^3/min. Determine the rate at which the radius of the balloon is increasing when the diameter of the balloon is 200 cm.

Answer 1

V = (4/3)πr^3
dV/dt = 4π r^2 dr/dt

plug in the given stuff

50 = 4π(100)^2 dr/dt
dr/dt = 50/(4π(100)^2 ) = .... cm/min

Answer 2

3.97cm/min