Answer:
You would want to divide 6 by 2, getting x=3.
Since the cross section is uniform, the depth of the water is irrelevant. The rate of change of height is the rate of change of volume divided by the area.
dh/dt = (dV/dt)/(π·r²)
= (9 ft³/min)/(π·(3 ft)²)
= 1/π ft/min ≈ 0.3813 ft/min
