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The average age of 10 children is 9 years 9 months…

September 7, 2022 by Prabhat

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The average age of 10 children is 9 years 9 months. The average of 9 children is 8 years 11 months. What is the age of the tenth child ?

A. 17 years 3 months
B. 18 years 4 months
C. 17 years 5 months
D. 18 years 3 months

Answer: Option A

Here is complete explanation of The average age of 10 children is 9 years 9 months….

Solution(By ExamCraze Team)

Average age of 10 children = 9 years 9 months
Sum of ages of 10 children = 9 × 10 + $$frac{9}{12}$$ × 10 = $$frac{390}{4}$$
Average age of 9 children = 8 years 11 months
Sum of age of 9 children = 8 × 9 + $$frac{11}{12}$$ × 9 = $$frac{321}{4}$$
Age of 10th child
= $$frac{390}{4}$$ - $$frac{321}{4}$$
= $$frac{69}{4}$$
= 17 years 3 months