I am not good in this kind of question so maybe 84?
suppose the full marks for each of them is 100 so for 5 of them it will be 500 cause if you if you multiply 100 full marks by 5 it will be 500
so the answer to this question is maybe 84?
cause if you add all of them with 84 the outcome will be 400 and if you divide the 400 by 5 it will be 80