Answer:
125
Step-by-step explanation:
The college administrators captured the 90 fraternity men and tagged them, then they returned them to the university campus.
Let there were x tagged fraternity men already on the university campus, so, the total number of tagged fraternity men on the campus become x+90.
Later a group of sorority women captured 215 tagged men, in which the 90 tagged men added by the college administration are included.
So, x+90=215
Hence, the number of fraternity men on the campus was 125.