Mrs. James gave a test to her two geometry classes. The 24 students in her first-period class had a class average (arithmetic mean) of 78. The average of the 26 students in her second-period class was 83. What was the average for all students taking the exam?
(A)79.4 (B)80.5 (C)80.6 (D)81.2 (E)81.4
C