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Average age of a Group of 40 boys is 15 years. A boy of age 20 years leaves the group and a new boy…

Total age of 40 boys is \(40\times 15=600\) years. After the 20-year-old leaves the total is 580, and the new group of 40 has total \(40\times 15.2=608\). The new boy's age…

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Average age of a Group of 40 boys is 15 years. A boy of age 20 years leaves the group and a new boy joins the group. If the average age of the new group becomes 15.2 years, then find the age of the new boy.

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Correct answer D

Total age of 40 boys is 40×15=60040\times 15=600 years. After the 20-year-old leaves the total is 580, and the new group of 40 has total 40×15.2=60840\times 15.2=608. The new boy's age is 608−580=28608-580=28 years.

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