Question
The average age of a class of 18 girls is 14 years. If 2
new girls having average age of 10 years join the class, then the average age of the class becomes:Solution
Total age of 18 girls = 18 × 14 = 252 years Total age of 20 girls = 252 + (2 × 10) = 272 years Therefore new average age = 272/20 = 13.6 years

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