Farmer samantha has a cylindrical grain silo with a diameter of 12 feet and a height of 40 feet. the silo is filled with grain that weighs approximately 48 pounds per cubic foot. samantha knows that each of the 20 cows on her farm will eat approximately 28 pounds of grain per day. if the grain silo is full, approximately how many pounds of grain will remain after the 20 cows eat for 100 days each? round your answer to the nearest whole pound.