Question

A spherical ballon is being filled with helium at a rate of 8cm^3/s. At what rate is its radius increasing, when it has been filling for 50 seconds?

Answer 1

dV/dt = 8cm^3/s
t = 50s
dr/dt - ?

Answer 2

V = 4/3*pie*r^3
dV/dt = 4*pie*r^2

Answer 3

woops sorry forgot dr/dt

Answer 4

dV/dt = 4*pie*r^2*(dr/dt)

Answer 5

8 = 4*pie*r^2*(dr/dt)
2/pie = r^2*(dr/dt)

Answer 6

was that all info given?

Answer 7

was it??