How many persons are older than S?       

The age of the second eldest person is 70 year which means the age of the grandmother is 70 year. V is the brother – in- law of O. V’s age is 2 year less than O’s age and O’s age is 6 year less than S’s age. R is the mother of S and her age is 2.5 of the age of her son. From these it is clear that O, V and S belongs to second generation and R is the grandmother whose age is 70 year. Further, only the father of T is sitting between Q and V. T does not belong to third generation. So, T belongs to second generation. The person who is sitting on the immediate left of O and immediate right of R is 18 year old while Q is 10 year old. S, who is sitting next to Q, is not sitting opposite to O. Q is the female member of the family. Q is 10 year old. So, Q is the granddaughter and 10 year old. R is 4 year younger than P. Means P is 74 year old. Rest U’s age is multiple of 4 but not a perfect square. As only remaining position is that U is the grandson and is 12 year old. The person who sits immediate right of V is a male but he is not U. So, from this case 3 will be eliminated. As we know that U can’t sit between R and O, so clearly T sit between R and O and U can’t sit to immediate right of Q so from this case 2 will be eliminated. Rest we know that the age of T is 18 year so she is the daughter of P and S is the son of R and is 28 year old. Rest V is 20 year old, O is 22 year old, O is 22 year old. So, the final arrangement is –