An open tank has the shape of a right circular cone. The tank is 8 feet across the top and 18 feet high. Water is pumped in through the bottom of the tank. (Assume water weighs 62.4 lb per cubic foot.) (a) How much work is done to fill the tank to a depth of 6 feet? foot-pounds (b) How much work is done to fill the tank from a depth of 12 feet to a depth of 18 feet? foot-pounds I am having so much trouble with this one -_- Help is appreciated GREATLY.