A controversial story comes out in the school newspaper. The number of students who have not heard about the story decreases at a rate that is proportional at any time to the number of students who have not heard the story at that time. There were 900 students who had not heard the story initially, and the number of students is divided by 3 every 4 days. How many students have not heard the story after 7 days? Round to the nearest student. students Stuck?