<p>
Harvard and Princeton used to require 3, but they recently (i believe in the 2008-2009 school year) changed that to 2:</p>
<p>Harvard: [Harvard</a> College Admissions § Applying: Requirements](<a href=“http://www.admissions.college.harvard.edu/apply/application_process/requirements.html#sat2]Harvard”>http://www.admissions.college.harvard.edu/apply/application_process/requirements.html#sat2)
Princeton: [Princeton</a> University | Standardized Tests](<a href=“http://www.princeton.edu/admission/applyingforadmission/faq/standardized_tests/#comp000046cc511c00000010b618e5]Princeton”>http://www.princeton.edu/admission/applyingforadmission/faq/standardized_tests/#comp000046cc511c00000010b618e5)</p>
<p>I don’t believe any college other than Georgetown requires or “recommends” 3. i don’t think the 3rd test’ll significantly help your application either (it does help, but i wouldn’t forcefully take a 3rd one just to put it on your application), but you might as well follow through now since you’ve begun the process. </p>
<p>
No, but most if not a large proportion of them do. You can almost always figure out whether a college super-scores by googling something like “[college name here] superscore,” or by checking the college’s website. All of the 3 that you mentioned (Harvard, Princeton, and Georgetown) super-score. Georgetown doesn’t consider your writing score.</p>