Question

The average age of a group of 4 friends was 23 years but after two years the oldest member of the group died and one year later another person joined there group now the average age of the group remains the same. What is the difference between the age of the new person added to the group and the age of person at the time of his death?
1. 6 years
2. 5 years
3. 8 years
4. 3 years
5. 2 years

Answer 1

Correct Answer - Option 4 : 3 years

The average age of the group = 23 yrs

⇒ Sum of age of the group = 23 × 4 = 92

The average age of the group 2 years later = 23 + 2 = 25 yrs

⇒ Sum of the age = 25 × 4 = 100

Now, let the age of the friend who died be x and 1 yr later another person joined there group and average age of group remains the same i.e 25 yrs

∴ New sum of the group = 25 × 4 = 100

⇒ 100 – x + y + 3 = 100

⇒ x – y = 3 

y → Age of new member added

∴ The difference between the age of the new person added to the group and the age of person at the time of his death is 3 yrs