Query statements are used to retrieve data from the database. Sometimes queries require query tuning because they suffer from performance issues in workspace. Apply query tuning on the following SQL queries to provide efficient performance:

1. SELECT SID, FNAME, AGE, GPA FROM STUDENT WHERE GPA != 0;
2. SELECT SID, FNAME, AGE, GPA FROM STUDENT WHERE GPA + 0.5 < 2.5;
3. SELECT SID, FNAME, AGE, GPA FROM STUDENT WHERE GPA > 3 OR AGE > 25;