We have 10 stadiums each holding 105 people. If each stadium has 8 events each year that’s 80 events per year in total. So there is 800 events throughout the 10 years (each year holding 80 events). To find the total number of people that attended the event we multiply the number of people that attended each event by how many events we had in total (105x800=84000) So, C,D and E apply.