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The answer is 6 students. I numbered each of the students, 1 for the front and 25 for the back. Julia was obviously no. 19. I counted from 25 back 14 places (starting with 25 so the solution would be right). I found that Jenny was no. 12. Then I counted the numbers between 12 and 19 and got 6.Chiu drew a diagram to help answer the problem: