If-Then Excel Logic question

Hello,

I am new to this forum and I apologize if this is a question that has previously been submitted. Here is the breakdown of what I would like to accomplish:

1. What I have: There are three columns. The first is a list of student names (sometimes repeated dependent on the third). The second is a list of corresponding class names they are registered in (also repeated dependent on the third column). The third is a list of attendance records by day.

2. What I would like to do: I wish to write a general formula that identifies that if both the row cells in column 1 (Names) are the same AND the row cells in column 2 (Class) are the same, then the numbers in column (3) need to averaged for those matched rows.

I've included an example set that may help visualize what I'm trying to do. So as an example, the formula would identify Drake, Janie from the first column AND Math 101 from the second column and then average the corresponding values (5/5 = 1). The formula would identify Drake, Janie from the first column AND Chem 101 from the second column and then average the corresponding values (2/5 = 0.4). Etc.

Thanks ahead for your help.