Question

The average age of a group of five friends is 78 years. If a friend, aged 48 years, is replaced by another friend, then the average age of each friend in the group will increase by 4 years. Find the age of the friend who was replaced.

Q: Answer-The average age of a group of five friends is 78 years. If a friend, aged 48 years, is replaced by a...

ATQ, Sum of the ages of 5 friends, initially 5 X 78 390 years Let the age of the new friend who joined the group y years Therefore, 390 - 48 y 5 X 78 4 Or, y 410 - 342 68 Therefore, age of the new friend 68 years Alternate Solution Age of the new friend age of the friend replaced increase in average age X number of friends So, age of the new friend 48 5 X 4 48 20 68 years