You're not giving enough detail. First, is the Combined Average better if higher? I assume the higher the attendance rate the better. Is it the same for the Cleanliness?
Why don't you rank all 3 and add them together (using a factor) (instead of using SUMPRODUCT). You don't say how you want to weight the rankings of each category. So lets say EXCEL was out of the picture and you had to do it by hand, what would you do? (Explain the process in words).