Not all boys who pass the College election examination choose to become King's Scholars. If they choose instead to belong to one of the <answer>24</answer> Oppidan Houses, they are known as Oppidan Scholars. Oppidan scholarships may also be awarded for consistently performing with distinction in School and external examinations. To gain an Oppidan Scholarship, a boy must have either three distinctions in a row or four throughout his career. Within the school, an Oppidan Scholar is entitled to use the letters OS after his name.
How many Oppidan houses are at Eaton?
24