In a family, there are seven members namely P, R, S, T, U, V and W. Then, how is S related to V?
I. P is the father of V. V is the brother of U. U is the daughter of R. 

So, how is S related to V is not known. 
II. R is the sister of T. S is the father of R. 

So, how is S related to V is not known.
III. W is the wife of S. P is the father of U. 

So, how is S related to V is not known.
Both statement I and II:
I. P is the father of V. V is the brother of U. U is the daughter of R. 
II. R is the sister of T. S is the father of R.

So, S is the grandfather of V. 
Thus, the data in statement I and statement II together is sufficient to answer the question.