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1. First step is to find the total age of all members of the family.
It is 30*8 = 240 years.
2. Second step is to find the total age of all children.
It is 6*9 = 54.
3. Now yo can calculate the total age of parents.
It is 240 - 54 = 186.
4. "the mother is four years younger than the father": M = F - 4.
5. From n.3, M + F = 186.
Substitute M = F - 4 from n.4. You will get
(F-4) + F = 186,
2F - 4 = 186 ====> 2F = 190 ====> F = = 95 Years.
Answer. Father is 95 years old.
My opinion is that this condition is absurd. Nonsense, in other words.