



 
Hi Emily, Suppose that $t$ is time measured in hours. The side length is a function of time so I am going to write the side length as $s(t)$ cm. The side length is decreasing at the rate of 5 cm per hour so $s'(t) = 5$ cm per hour. The volume of the cube is given by $V(t) = s(t)^3$ cubic centimeters. Differentiate this expression implicitly with respect to $t$ and then solve for $V'(t)$ when $s(t) = 25$ cm. Penny  


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