Class A has 25 students averaging 70 marks. Class B has 35 students averaging 60 marks. What is the combined average?
A$65$
B$64.17$
C$66$
D$67.5$
Answer & Solution
Correct answer: B. $64.17$
Combined = (25×70 + 35×60)/(25+35) = (1750 + 2100)/60 = 3850/60 = 64.17. Simple averaging (65) would only be correct for equal class sizes.
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