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In a class there are 40 girls and their average age is 16 years. One girl aged 17 years leave the school and another joins, and their average age becomes 15.95 years. What is the age of the new girl?

In a class there are 40 girls and their average age is 16 years. One girl aged 17 years leave the school and another joins, and their average age becomes 15.95 years. What is the age of the new girl? Correct Answer 15 years

Sum of total age of 40 girls initially = 16 × 40 = 640 years

Total age of 39 girls = 640 – 17 = 623 years

New total age = 40 × 15.95 = 638 years

Age of new girl = 638 – 623 = 15 years

∴ Age of new girl is 15 years

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