Question: what is top 20 percent of class?
Answer: Divide your class rank by the number of students in your grade, multiply by 100, then subtract that number from 100. For example, if there are 600 students in your grade and you are ranked 120th, then you are in the 80th percentile because (120/600)*100=20, and 100-20=80. You are also in the top 20% of your class.