Query to calculate marks based on combo box

[I am alive]

Hello everyone. I have attached my database. I am trying to calculate marks total marks scored by a learner based on subjects he or she is taking. Also average of those marks and position of the learner (ranking). A learner can do 5 subjects and another learner can do 7 subjects and another one can do 10 subjects. I would really appreciate if someone can help me come up with a query or a function.
Student A
English
Kiswahili
Physics
Chemistry
Biology
Student B
English
Kiswahili
Mathematics
Physics
Chemistry
CRE
Geography
Student C
History
Mathematics
Physics
Chemistry
Biology
Geography
Computer studies
French
Arabic
German.
Any help will be highly appreciated

 

[mike60smart]

See rptStudentsGrades in the attached

 

[I am alive]

Thank you so much. I really appreciate. God bless you

 

[mike60smart]

Also see rptTotalMarks in the attached

 

[I am alive]

Also see rptTotalMarks in the attached

Also see rptTotalMarks in the attached

You are genius. Thanks so much. I would wish to have a datasheet report for subjects and total marks together based on subjects done e.g
name Grade Eng kis total
1. Errickson . Form 2 88. 34 115
2. Charity. Form 2 67. 76. 133
3. Rooney. Form 2. 98. 86. 184
4. Ngeno. Form 3. 77. 100. 177
Total marks. 330 296 609
Average. 83. 74. 152

English- 330/4 = 82.5
Kiswahili- 296/4=74
Total 609/4= 152.25
Thanks in advance. I really really appreciate from deep down my heart what you have done especially going an extra mile. God will bless you so much. Once again thank you so much.

 

[I am alive]

Edited

You are genius. Thanks so much. I would wish to have a datasheet report for subjects and total marks together based on subjects done e.g
name Grade Eng kis total
1. Errickson . Form 2 88. 34 115
2. Charity. Form 2 67. 76. 133
3. Rooney. Form 2. 98. 86. 184
4. Ngeno. Form 3. 77. 100. 177
Total marks. 330 296 609
Average. 83. 74. 152

Average for English-(88+67+98+77=330/4=82.5)
Average for Kiswahili- (34+76+86+100= 296/4= 74)
Average of Total marks scored by all students based on subjects done
(115+133+184+177=609/4= 152.25)

Thanks in advance. I really really appreciate from deep down my heart what you have done especially going an extra mile. God will bless you so much. Once again thank you so much.

 

[mike60smart]

See the rptStudentsAverages in the attached

 

[I am alive]

Thank you so much. I really appreciate. God will bless you abundantly. Once again thank you.