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
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Answer:
Up
Step-by-step explanation:
Y= 1x^2 + 3x + 9
Y= Ax^2 + Bx + C
To determine which way a parabola opens just look at the coefficient (the number) of the x^2 - Always use the coefficient that is beside the x^2
So, if the coefficient A is positive the parabola is opening upward
if the coefficient A is negative the parabola is opening downward
1/3 is the slope.
x-3y=2
-3y=-x+2
y=(1/3)x+2/3
