75% of the students are shorter than 68 inches.
Of the 8 students, only 2 are 68 inches tall or more, meaning theres 1/4 or 25% of students who are taller than 68 inches. That being said, that means there are 3/4 or 75% of students shorter than 68 inches. Thus meaning 75% is your answer.
I hope this helps!
