What are the percentiles of her GRE scores?

The score does not provide sufficient information, it is the percentile of the score that matters. GRE may not be the only criterion. Sometimes the grade point average (GPA) is also very important, or even more important. The immigration status of the student could also make a difference: foreign students may need much higher GRE and GPA. It depends on how competitive the program is.

Many PhD programs weigh several factors: in addition to GRE and GPA, the personal statement and reference letters are also very important. If the statement and letters are very strong, specially the letters, lower grades might be OK. Masters programs might be different.