Given
Total students = 560
Average age of boys = 12 years
Average age of girls = 11 years
Average age of school = 11 years 9 months = 11.75 years
Concept Used
Mixture and Allegation
Solution
Ratio of Boys : Girls = (Mean - Girls Avg) : (Boys Avg - Mean)
Ratio = (11.75 - 11) : (12 - 11.75)
Ratio = 0.75 : 0.25
Ratio = 3 : 1
Total parts = 3 + 1 = 4
Number of girls =
Number of girls = 140
Final Answer
So the correct answer is (d)
English
10 Questions
10 Marks
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