A group of teachers and students go on a school trip. For every teacher on the trip, there are four male students and five female students.
If there are 30 female students on the trip, how many male students are there?
Let's assume the number of teachers on the trip is T.
So, the number of male students is 4T, and the number of female students is 5T.
Given that there are 30 female students on the trip, 5T = 30.
Dividing both sides of the equation by 5, we find T = 30/5 = <<30/5=6>>6.
Therefore, there are 4T = 4*6 = <<4*6=24>>24 male students on the trip. Answer: \boxed{24}.
Let's first determine the number of teachers on the trip.
Given that for every teacher, there are four male students and five female students, we can determine the ratio of male students to female students as 4:5.
Since there are 30 female students on the trip, we can calculate the number of male students as follows:
5 female students = 4 male students
30 female students = (4/5) * 30 male students
30 female students = 24 male students
Therefore, there are 24 male students on the trip.