At a certain instant the volume of a cube is and is increasing at

MATHEMATICS · Single correct · A Level · Mathematics · Differentiation · Differentiation

Problem

At a certain instant the volume of a cube is

125\,\text{cm}^3

and is increasing at

30\,\text{cm}^3\!\text{/s}

. What is the rate of change of its surface area at that instant? (a)

60\,\text{cm}^2\!/\text{s}

(b)

12\,\text{cm}^2\!/\text{s}

(c)

24\,\text{cm}^2\!/\text{s}

(d)

72\,\text{cm}^2\!/\text{s}