The score which Lisa should get in her fourth exam of school to get exactly 80% in the course is 64.
The average of the group of numbers is the ratio of the sum of all the numbers of the group to the total number of the group.
Lisa is currently taking physics as one of her electives in school.
Her grade at the end of the year is determined by the average of four exams, each worth 100 points.
She got exactly 80% in the course. Let she scores x marks in her fourth exam. Thus,
[tex]\dfrac{84+92+80+x}{4}=80\\256+x=80\times4\\x=320-256\\x=64[/tex]
Hence, the score which Lisa should get in her fourth exam of school to get exactly 80% in the course is 64.
Learn more about the average here;
https://brainly.com/question/20118982