Here is a great explanation from Harvard University:
"Financial aid is completely need-based and considers many factors, such as your family’s income, assets, size, and unusual expenses."
"Our financial aid officers will work closely with you and your family to determine your demonstrated need and your family’s expected contribution. For many families, this is between zero and 10 percent of family income. Because everyone's circumstances are unique, it's difficult to summarize the many financial aid options and policies that exist."
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