Hi, thank you for posting your question here at Brainly.
This problem can be solved easily by applying ratio and proportion. In this case, the ratio between those who go to college and those who do not is 7/4. Then, when there are 28 students, you can determine the number of which who don't go to college by using the 7/4 ratio value
7/4 = 28/x
x = 16
Thus, 16 students did not go on to college.