The average age of the father and his five children is 10 years, which is decreased by 6 years if the age of the father is excluded. The age of the father is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 40 years.
Let total age of 5 children = S
(F + S)/6 = 10
⇒ F + S = 60 .....(1)
When father is excluded, the average age of 5 children = 10 - 6 = 4 years
⇒ S/5 = 4
⇒ S = 20
⇒ F = 60 - 20 = 40 years