Answer:
43.78
Explanation:
In this case, the formula for mean can be as followed:
Let the sum of all student scores for class A and class B be A and B respectfully,
For Class A,
A/28 = 34
A/28 = 34A = 952
For Class B,
B/8 = 78
B/8 = 78B = 624
Now to find the mean score of both classes using the same formula,
Mean = (952+624)/(28+8)
= 43.77777777777778
≈ 43.78