The average score of all the students in both classes is 84.
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:
78
Step-by-step explanation:
A
The function is :
y = √(x-12), x≥12
To find the inverse function, we interchange x and y, and then make y the subject again.
So interchanging x and y we have:
x = √(y-12)
Squaring both sides gives;
x² = y-12
Now making y the subject we have,
y = x² +12
x≥0.
Therefore the inverse function is;
y = x² +12, x≥0.
Hence the correct answer is C.
