10. (10 points) Xiao Ming and Xiao Hua are in Class 6 (1), which has between 20 and 30 students, and each student has a unique birthday. Xiao Ming says: “The number of students older than me is twice the number of students younger than me.” Xiao Hua says: “The number of students older than me is three times the number of students younger than me.” How many students are in this class?