The average (arithmetic mean) age of the people in a certain group was 35 years before one of the members left the group and was replaced by someone who is 12 years older than the person who left. If the average age of the group is now 37 years, how many people are in the group?

The average age of a group of 8 persons was 14 years.A person with age 28 years left the group and a new person with age 16 years joined the group.Find the new average age of the group.

Two years ago the mean age of 40 people was 11 years. Now a person left the group and the mean age has changed to 12 years. Find the age of the person who left the group.

There are 15 members in a group whose average age is 25 years and one member left the group then the average increased by 1 year then the age of the member who has left, is:

Average age of a group of 30 boys is 16 years. A boy of age 19 leaves the group and a new boy joins the group. If the new average age of the group is 15.8 years, find the age of the new boy.

The mean age of a combined group of men and women is 25 years. If the mean age of the group of men is 26 years and that of group that of women is 21 years, then find the percentage of men and women in the group.

The average age of a couple is 25 years. The average age of the family just after the birth of the first child was 18 years. The average age of the family just after the second child was born was 15 years. The average age of the family after the third and the fourth children (who are twins) were born was 12 years. If the present average age of the family of six persons is 16 years, how old is the eldest child ?

Average age seven persons in a group is 30 years .The average age of five person of this group is 31 years .What is the average age of the other two person in the group ?

If out of 10 selected students for an examination, 3 were of 20 years, age, 4 or 21 and 3 of 22 years, the average age of the group is