Arihant Expert Team Solutions for Chapter: Average, Exercise 1: Practice Exercise

The average age of $60$ boys in a class was calculated as $12$ years. It was later realised that the actual age of one of the boys in the class was $12.5$ years, but it was calculated as $14$ years. What is the actual average age of the boys in the class?

The average age of boys in a class is $12$ years. If the age of the principal is included, the average becomes $13$ years. What is the age of the principal?

The average age of a brother and sister was $35$ years, five years ago. What will be their average age (in years) at present?

The average age of Ram, Hari and Gopal is $42$ years. If their ages are in the ratio of $2:3:4$ respectively, what is the age of Hari in years?

The average age of five officers in a department is $32$ years. If the age of their supervisor is added, the average is increased by $1$. What is the supervisor’s age?

The average age of a father and his two sons is $27$ years. Five years ago, the average age of the two sons was $12$ years. If the difference between the ages of two sons is $4$ years, then the present age of the father is:

The average age of eight people is increased by $2$ years, when one of them, whose age is $24$ years is replaced by a new person. The age of the new person is:

The average age of eight men is increased by two years when two of them, whose ages are $21$ and $23$ years, are replaced by two new men. The average age of the two new men is: