To illustrate, here's a sample calculation of the TOTAL PERCENT SCORE for a hypothetical student:
Exam, Query and Homework Data for John Doe

Exam Scores      Midterm Exam    76 (out of 100)

                            FINAL    83 (out of 100)

Query Total        15 (out of 20)

Homework Total        69 (out of 80)


 
Calculation of TOTAL PERCENT SCORE  for John Doe

His Final Exam score (83) is better than his midterm score (76), so we replace the 76 with 83.

So John has earned  83 + 83 + 15 + 69 =  250 points out of a possible 300.

           John Doe's TOTAL PERCENT SCORE = (250/300) X 100 = 83.3

So what is his letter grade for the course?  I will not determine how 83.3 translates into a letter grade until after the final. But the information below gives some guidelines to help John think about letter grades.