The base of a pyramid-shaped tank is a square with sides of length 12 feet, and the vertex of the pyramid is 10 feet above the base. The tank is filled to a depth of 4 feet, and water is flowing into the tank at the rate of 2 cubic feet per minute. Find the rate of change of the depth of water in the tank. (Hint: The volume of a pyramid is given by V=(1/3)Bh where B is the area of the base and h is the height of the pyramid.) The answer in the back of the book is 25/648. I got 25/162. I think the book made a mistake, but I'm not sure. Can I get any confirmation?