In the shape of cubes, by allowing the solution of Sodium Chlorate crystals to grow, the volume of such a cube is chlorate and water to evaporate slowly. Suppose sodium 300 mm/hr. If the cube has a side length x, at what rate is the side decreasing at a rate of length decreasing at the instant x = 10 mm?
900 mm/hr
3 mm/hr
mm/hr
10 mm/hr