The average class size at belmont middle school is 30 students, which is 25% larger than it was a decade ago. what was the average class size then?

So what you do is do 25% of 30. Then you divide 25 by 100 so it can be a number. It would be 0.25. Then you time it by 30. 0.25x30=7.5. Ur done there then you minus it by the original number. 30-7.5=22.5. I HOPED I HELPED