Class A has 13 pupils and class B has 30 pupils.

Both classes sit the same maths test.
The mean score for class A is 45.
The mean score for both classes is 66.
What is the mean score (rounded to 1 DP) in the maths test for class B?

3 answers

(13*45 + 30*66) / (13+30) = ____
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