Question on Probability in a Class Room

Topic : Probability

Question : In a class of 72 students, 44 are girls and,of these, 12 are going to college. Of the 28 boys in the class, 9 are going to college. If a student is selected at random from the class, what is the possibility that the person chosen is not going to college

Answer :
Not going to college means complement that students goes to college
So 1 is the probability that student goes to college
and no of students going to college is given by 9+12/72 = 7/24
= 1 - 7/24 = 24-7 / 24 = 17/24