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
Solution(By Examveda Team)
Average age of 10 children = 9 years 9 monthsSum 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
Related Questions on Average
A. 125 km/hr
B. 75 km/hr
C. 135 km/hr
D. 120 km/hr
Join The Discussion