Answer:
2) 20 students
4) 28 students
Question 2 is 25% - but it's asking how many. If you know the total number of students multiply that times .25 and that number is your answer. So .25 x 80 = 20
Question 4 is 35% also multiplied times the total number of students. So it would be the total number of students multiplied times .35.
So .35 x 80 = 28
Both of these questions want the number of students, not the percent.