+5 A container in the shape of an inverted cone of radius 3 metres and vertical height 4.5 metres is initially filled with liquid fertiliser. This fertiliser is released through a hole in the bottom of the container at a rate of 0.01m^3 per second. At time t seconds the fertiliser remaining in the container forms an inverted cone of height h metres [The volume of a cone is V=1/3(pi)r^2h] i) show that h^2dh/dt=-9/400(pi) ii) Express h in terms of t iii) Find the time it takes to empty the container, giving your answer to the nearest minute
