There are 1200 students at the community college. Each professor teaches 4 classes and each student takes 5 classes. There are 30 students and 1 professor for each class. How many professors are there?

We don't provide answers to homework. But we can help you along if you show us your attempt and where you are getting stuck. To help get you started: if each student takes 4 classes what is the total number of 'class-seats"?