Please answer a question about the following article about Washington University in St. Louis:

Washington University has over 300 undergraduate student organizations on campus. Most are funded by the Washington University Student Union, which has a $2 million plus annual budget that is completely student-controlled and is one of the largest student government budgets in the country. Known as SU for short, the Student Union sponsors large-scale campus programs including WILD (a semesterly concert in the quad) and free copies of the New York Times, USA Today, and the St. Louis Post-Dispatch through The Collegiate Readership Program; it also contributes to the Assembly Series, a weekly lecture series produced by the University, and funds the campus television station, WUTV, and the radio station, KWUR. KWUR was named best radio station in St. Louis of 2003 by the Riverfront Times despite the fact that its signal reaches only a few blocks beyond the boundaries of the campus. There are 11 fraternities and 9 sororities, with approximately 35% of the student body being involved in Greek life. The Congress of the South 40 (CS40) is a Residential Life and Events Programming Board, which operates outside of the SU sphere. CS40's funding comes from the Housing Activities Fee of each student living on the South 40.

How many fraternities are located at Washington University?
11