Keywords:
tennis shoes, class, students, percentage, rule of three
For this case we have that the number of students, in Jamal's class, who wear tennis shoes is given by 24, out of a total of 30 students in the class. You want to know the percentage of students in the class who wear tennis shoes, to determine if Jamal is right. For this, we apply a rule of three:
30 students --------------> 100%
24 students --------------> x
Where x represents the number of students who wear tennis shoes. So:

Thus, 80% of the students in Jamal's class wear tennis.
Jamal was not right.
Answer:
Jamal was wrong. 80% of their class wears tennis shoes.