Could you please help me solve the following problem?

Example 6. A tank lled with oil is in the shape of a downward-pointing right rectangular pyramid with its vertical axis perpendicular to ground level. The height of the tank is 8 feet, the square top of the tank has length 4 feet, and that the oil inside the tank weighs 55 pounds per cubic foot. (a) item If the tank were completely full, how much work would it take to pump oil from the tank to the level at the top of the tank? (b) If the tank were completely full, how much work would it take to pump oil from the tank to 3 feet above the top of the tank? (c) If the tank is half full (volume), is it true that it will take half as much work to pump the water out of the tank? Explain your thinking