Answer:
D.
Step-by-step explanation:
3-6-3-6×7=-48
3-7*(-3)-6=6
(3-7)×(-3)-6=6
(3-7)(-3-6)=36
Hope this picture helps you
The average score of all the students in both classes is 84.
<h3>How to calculate the average?</h3>
The class with 30 students had an average score of 80 on a test. The total score will be:
= 30 × 80
= 2400
A class with 20 students had an average score of 90 on the same test. The total score will be:
= 20 × 90
= 1800
Total scores = 2400 + 1800 = 4200
Number of students = 20 + 30 = 50
The average score will be:
= Total score / Total students
= 4200 / 50
= 84
Learn more about average on:
brainly.com/question/24313700
#SPJ1
