Answer:
0.64ft/min
Explanations
The rate of change of the water in the conical flask is expressed as;

Given the volume of the shaded region expressed as:

Substitute the given values and expression into the rate of change as shown;

Simplify and determine dh/dt, the rate at which the height is increasing

Therefore the height of the water in the tank is increasing at a rate of 0.64ft/min