Answer :
By using the concept of rate of change, it is obtained that
Water level is falling at the rate of [tex]\frac{2}{9\pi}[/tex] m per minute
What is rate of change?
Suppose there is a function and there are two quantities. If one quantity of a function changes, the rate at which other quantity of the function changes is called rate of change of a function.
Here the concept of rate of change has been used
Let the radius of cone at any point be r m and height be h m
Volume of cone = [tex]\frac{1}{3}\pi\times r^2\times h[/tex]
Now,
By the concept of similarity,
[tex]\frac{r}{h} = \frac{4}{16}\\\\\frac{r}{h} = \frac{1}{4}\\\\r = \frac{1}{4}h[/tex]
Volume of cone (V) =
[tex]\frac{1}{3}\times \pi \times (\frac{1}{4} h)^2\timesh\\\\\frac{1}{48}\times \pi \times h^3\\[/tex]
[tex]\frac{dV}{dt} = \frac{1}{48} \times \pi \times 3h^2\times \frac{dh}{dt}\\\\\frac{dV}{dt} = \frac{1}{16} \times \pi \times h^2\times \frac{dh}{dt}\\\\[/tex]
Now,
[tex]\frac{dV}{dt} = -2,\ h = 12[/tex]
So,
[tex]-2 = \frac{1}{16}\times \pi \times (12)^2 \times \frac{dh}{dt}\\\\\frac{dh}{dt} = -\frac{2 \times 16}{\pi \times 12 \times 12}\\\\\frac{dh}{dt} =- \frac{2}{9\pi}[/tex]
So water level is falling at the rate of [tex]\frac{2}{9\pi}[/tex] m per minute
To learn more about rate of change, refer to the link-
brainly.com/question/24313700
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