Different institutions may have different methods of grading performances. You can estimate you GPA using online GPA calculators. Here are some of the GPA calculators that can help you know what you must do to get 3.0 GPA.

Back2College.com Calculator:
http://www.back2college.com/gpa.htm

Foothill College Calculator:
http://www.foothill.edu/transfer/counseling.calc.html

Indiana University GPA Calculation chart:
http://psych.iupui.edu/Users/dappleby/Undergrad/gpa.htm

I guess links I provided will help you.

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