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Determine the rate at which the water depth is increasing when the depth is $4\text{ m}$, and give your answer in $\text{cm}$ per minute.
Mathematics 9709 · AS & A Level · Differentiation
Differentiation — practice question
In a large industrial water tank, if the water depth is x metres, then the water volume V \text{ m}^3 in the tank is given by $V = 243 - \frac{1}{3}(9 - x)^3$. The tank is being filled at a steady rate of $3.6\text{ m}^3$ per hour.