Free GMAT Practice Question

Every student in a certain seminar either completed the optional problem set or did not. On the final assessment, the mean score of the students who completed the problem set was 84, the mean score of the students who did not complete it was 69, and the mean score for the seminar as a whole was 75. The seminar has more than 20 students and fewer than 30 students.

In the table, select the number of students who Completed the problem set and the number who Did not complete it. Make only two selections, one in each column.