I got this question from my teacher to be completed by the beginning of Dec. It goes like this. sheep eat grass at a fixed rate grass grows at a fixed rate 1 sheep in a pen eats grass forever 8 sheep eat grass in 5 days then starve 9 sheep eat grass in 4 days then starve I figure from the 8 sheep that 20% is eaten each day so by day five all the grass is gone and no new new grass is available. This led me to 1 sheep eating 2.5% a day. By day 40 all grass would be gone except enough grass has grown to replace eaten grass. I think that 12.5% is replaced every 5 days (this is my calculation). Can anyone help me? The question is what is the maximum amount of sheep that can be kept in a pen and eat grass forever?