In a class where 25% of the students are female, the average score in an exam was 16.5. Excluding three female students whose total score was 21, the average score of the remaining students would be 17, while the average score of the remaining female students would be 13.25. What is the average score of the male students?

Let's break down the problem step by step:

1. Let's denote the total number of students as 'T', the number of female students as 'F', and the number of male students as 'M'. From the problem, we know that F = 0.25T.

2. The total score for all students is T * 16.5.

3. If we exclude the three female students, the total number of students becomes T - 3, and the total score becomes T * 16.5 - 21. The average score of these remaining students is 17, so we have the equation (T * 16.5 - 21) / (T - 3) = 17.

4. The total score for the remaining female students is (F - 3) * 13.25. Since F = 0.25T, we can substitute F into the equation to get (0.25T - 3) * 13.25.

5. The total score for the male students is the total score for all remaining students minus the total score for the remaining female students, which is (T - 3) * 17 - (0.25T - 3) * 13.25.

6. The average score for the male students is the total score for the male students divided by the number of male students, which is M = T - F. Substituting F = 0.25T into the equation, we get M = T - 0.25T = 0.75T.

7. Therefore, the average score for the male students is ((T - 3) * 17 - (0.25T - 3) * 13.25) / (0.75T).

8. Solving this equation will give us the average score for the male students.