Mrs. Garcia's homeroom sold more magazine subscriptions per student. You can divide the number of magazine subscriptions by the number of students for each homeroom. For Mr. Brown's homeroom you get 72/24 which is 3 per student. For Mrs. Garcia's homeroom you get 98/28 which is 3.5 per student. Since 3.5 is greater than 3, you know that Mrs. Garcia's homeroom sold more per student.
