Mark M. answered • 07/21/15

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**Let V = volume of water at time t minutes**

**h = depth of water at time t minutes**

**Given: dV/dt = 1.84 ft**

^{3}/min**Find: dh/dt when h = 4.2 ft**

**V = πr**

^{2}h = π(15)^{2}h = 225πh**So, dV/dt = 225π(dh/dt)**

**1.84 = 225π(dh/dt)**

**dh/dt = 1.84/(225π) ≈ 0.0026 ft/min**

**Note: dh/dt is constant for any value of h, 0 < h < 6.**