Aptitude - Average - Discussion

First, we need to calculate the SUM OF AGES for each of them,
We know that ( Average = Sum Of Ages/Number of members).
Then, (Sum Of Ages = Average * Number of members).

∴ Sum Of Ages for Grand Parents = 67 * 2 = 134.
& Sum Of Ages for Parents = 35 * 2 = 70.
& Sum Of Ages for Grand Children = 6 * 3 = 18.

Now, Let's calculate the Average Age for the whole family:
= Sum Of Ages of the whole family/Number of family members.
= (134 + 70 + 18) / (2+2+3).
= 222 / 7 = 31. 5/7.

Agree @Pavithra Uh.

Parent means (Mom or Dad) , parents means (both Mom and Dad) , grandparents means (grandma and grandpa (single set)).

Single set = (grandpa and grandma) , Double set = ( (Grandpa and Grandma) , (Grandpa and Grandma) ) likewise.

In question, the Average age of Grandparents (Single set) is 67.

So, we multiply by 2.

Suppose in our question 3 Grandparents means we multiplied by 3.

Correct me, If I am wrong.

In the question they have already given as average age of grandparents and so on. So why should we multiply that by 2 again? Please, tell me.

Can't understand anything, please explain me.

How come 5/7? Explain it.

Grands = 67*2=134,
Mother and Father = 35*2=70,
Child's = 6*3=18.

= 134+70+18/7,
= 222/7,
= 31.71.

How come 5/7? Please explain to me.

Why is 31 5/7 is come?

How come 31 5/7 at final? Please explain me.

2 GP(Avg age 67) ,
2 P(Avg age 35),
3 Grand CHILD(Avg age 6).
(67*2+35*2+3*6)/7(2+3+2).