An inverted pyramid-shaped tank with square cross section shown in the figure below is 10 ft tall with 81 ft cross sectional area at the very top. +10 lb The tank is full up to the 7 ft mark with liquid of weight density 503 How much work (in ft-lb) is required to pump all of the liquid 3 ft above the top of the container? (Round your answer to the nearest integer.) ft-lb