alleryA class has 40 boys averaging 65 marks and 20 girls averaging 80 marks. What is the overall average?
A$72.5$
B$70$
C$68.33$
D$74$
Answer & Solution
Correct answer: B. $70$
Weighted average = (40×65 + 20×80) / 60 = (2600 + 1600)/60 = 4200/60 = 70. (Simple average 72.5 is the trap.)
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