The volume of a cube decreases at the constant rate of 12 cubic inches per minute. At what rate (in square inches per minute) is the surface area shrinking when an edge of the cube is 4 inches long?

Question

anonymous · Answer

find the relation between the surface area and the volume
then take derivatives

anonymous · Answer

i don't know it off the top of my head, do you?

xbeenchantedx · Answer

I only know the answer choices.
A. 1/4
B. 3/8
C. 12
D. 24
E. 48

xbeenchantedx · Answer

I know you probably have to use the derivative but I got stuck in the beginning.

anonymous · Answer

i am not really interested in the choices, don't think you can eyeball it 
need a relation between the surface area and the volume

anonymous · Answer

if the edge is $x$ then $V(x)=x^3$ and $S(x)=6x^2$ 
solve for $V$ in terms of $S$

anonymous · Answer

i just googled it, easier than doing the algebra
try that first, then we can continue

anonymous · Answer

did you find it?