She would need to make an 89 on her last test. I hope this helped ^^
What I did is I put a made a list in ascending order (Least to greatest). Next, I added a number starting from 80 and then counted up. I added every number together and divided it by 5 every time I changed the number. Finally I got to the number 89 and it totaled to be 85.
The answer is a. increase energy efficiency. This means that we now use less energy to do more thanks to many advances in technology. It could also be due to the use of alternative sources of power such as the sun or win. These new sources provide energy without causing pollution.