Question 1170380
Starting with the equation for the volume of a sphere:
{{{ V = (4/3)pi*r^3 }}}<br>
you can relate the rate of change of volume WRT time (dV/dt) to the product (dV/dr)*(dr/dt):
{{{ dV/dt = (dV/dr)*(dr/dt) = 4pi*r^2 * (dr/dt) }}}   ... (1)<br>

Plugging into (1) the known values:
{{{ 3 = 4pi(5)^2 * (dr/dt) }}}<br> 

and solving for dr/dt:
{{{ dr/dt = 0.00955 }}} ft/min