



 
Lyudmyla, The volume of a cone is given by
where r is the radius and h is the height. The radius and the height of your cone are changing so r, h and V are functions of t. Differentiate both sides of the equation with respect to t. You need to use the product rule so you get
which is
or
Substitute the values you know and solve for dV/dy. Harley  


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