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      Exam 1    83 (out of 100)
                            Exam 2    68 (out of 100)
                            Exam 3    79 (out of 100)

                            FINAL    84 (out of 100)

Query Total        16 (out of 20)

Homework Total        67 (out of 80)


 
Calculation of TOTAL PERCENT SCORE  for John Doe

His Final Exam score (84) is better than his Exam 2 score (68), so we replace the 68 with 84.

So John has earned  83 + 84 + 79 + 84 + 16 + 67 =  413 points out of a possible 500.

           John Doe's TOTAL PERCENT SCORE = (413/500) X 100 = 82.6

So what is his letter grade for the course?  I will not determine how 82.6 translates into a letter grade until after the final.  So don't bother asking.  (But the information below gives some guidelines to help John think about letter grades.)