Answer:
87.25%
Step-by-step explanation:
Data given in the question
Before the final exam for a course, the average percentage is 85%
The counting percentage of the course grade is 15%
So by considering the above information, the best course grade your friend is
=
= 0.7225 + 15
= 87.25%
The remaining percentage is come from
= 100% - 15%
= 85%
Hence, the best course grade is 87.25%