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 t…

The mean of 1<sup>2</sup>, 2<sup>2</sup>, 3<sup>2</sup>, 4<sup>2</sup>, …

A library has an average of 510 visitors on Sundays and 240 on other days. What is the average number of visitors per da…

The average weight of 12 crewmen in a boat is increased by $$\frac{1}{3}$$ kg, when one of the crewmen whose weight is 5…

The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was…

The average age of students of a class is 15.8 years. The average age of boys in the class is 16.4 years and that of the…

In a pre school, the average weight of 30 girls in a class among 50 students is 16 kg and that of the remaining students…

Six numbers are arranged in decreasing order. The average of the first five numbers is 30 and the average of the last fi…